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Know Thyself 357 Merch Secretum Scientia Sweatshirt

Rated 4 out of 5 based on 3 customer ratings

(4 customer reviews)

Original price was: $19.99.Current price is: $17.99.

Estimated delivery dates: Aug 12, 2026 - Aug 20, 2026

Style

Color

Size

XS
S
M
L
XL
2XL
3XL
4XL
5XL
11oz
12oz
15oz
20oz
30oz
Color Changing 11oz
Color Changing 15oz
One Size
Pack 1
Pack 3
Pack 5

Clear

Sizing chart

Don’t have your favorite color, size? Please contact us directly if you would like to have your own one.

Unisex Standard T-Shirt

Size	Chest Width	Shirt Length
S	18 in	28 in
M	20 in	29 in
L	22 in	30 in
XL	24 in	31 in
2XL	26 in	32 in
3XL	28 in	33 in
4XL	30 in	34 in
5XL	32 in	35 in

Note: Allow for a tolerance level of 1 inch

Unisex Hoodie

Size	Chest Width	Shirt Length	Sleeve Length
S	20 in	27 in	33.5 in
M	22 in	28 in	34.5 in
L	24 in	29 in	35.5 in
XL	26 in	30 in	36.5 in
2XL	28 in	31 in	37.5 in
3XL	30 in	32 in	38.5 in
4XL	32 in	33 in	39.5 in
5XL	34 in	34 in	40.5 in

Note: Allow for a tolerance level of 1 inch

Unisex Sweatshirt

Size	Chest Width	Shirt Length	Sleeve Length
S	20 in	27 in	33.5 in
M	22 in	28 in	34.5 in
L	24 in	29 in	35.5 in
XL	26 in	30 in	36.5 in
2XL	28 in	31 in	37.5 in
3XL	30 in	32 in	38.5 in
4XL	32 in	33 in	39.5 in
5XL	34 in	34 in	40.5 in

Note: Allow for a tolerance level of 1 inch

Men's Zip Hoodie

Size	Chest Width	Shirt Length	Sleeve Length
S	19.25 in	27 in	33.5 in
M	21.25 in	28 in	34.5 in
L	23.25 in	29 in	35.5 in
XL	25.25 in	30 in	36.5 in
2XL	27.25 in	31 in	37.5 in
3XL	29 in	32 in	38.5 in

Note: Allow for a tolerance level of 1 inch

Men's Long Sleeved T-Shirt

Size	Chest Width	Shirt Length	Sleeve Length
S	18 in	28 in	33.5 in
M	20 in	29 in	35 in
L	22 in	30 in	36.5 in
XL	24 in	31 in	38 in
2XL	26 in	32 in	39.5 in
3XL	28 in	33 in	39.5 in
4XL	30 in	34 in	39 in
5XL	32 in	35 in	40.5 in

Note: Allow for a tolerance level of 1 inch

Men's V-Neck T-Shirt

Size	Chest Width	Shirt Length
S	18 in	28 in
M	20 in	29 in
L	22 in	30 in
XL	24 in	31 in
2XL	26 in	32 in
3XL	28 in	33 in

Note: Allow for a tolerance level of 1 inch

Men's Tank Top

Size	Chest Width	Shirt Length
S	18 in	28 in
M	20 in	29 in
L	22 in	30 in
XL	24 in	31 in
2XL	26 in	32 in
3XL	28 in	33 in

Note: Allow for a tolerance level of 1 inch

Ladies Long Sleeve T Shirt

Size	Chest Width	Shirt Length
S	18 in	28 in
M	20 in	29 in
L	22 in	30 in
XL	24 in	31 in
2XL	26 in	32 in
3XL	28 in	33 in

Note: Allow for a tolerance level of 1 inch

Ladies T Shirt

Size	Chest Width	Shirt Length	Sleeve Length
S	17.25 in	25.5 in	13.25 in
M	19.25 in	26 in	14 in
L	21.25 in	27 in	14.75 in
XL	23.25 in	28 in	15.75 in
2XL	25.25 in	28.5 in	16.75 in
3XL	27.25 in	29 in	17.5 in

Note: Allow for a tolerance level of 1 inch

Ladies Hooded Sweatshirt

Size	Chest Width	Shirt Length	Sleeve Length
S	20 in	26 in	32 in
M	22 in	27.5 in	33 in
L	24 in	28 in	34.5 in
XL	26 in	29.5 in	35.5 in
2XL	28 in	30 in	37 in

Note: Allow for a tolerance level of 1 inch

Ladies Tank Top

Size	Chest Width	Shirt Length
S	15 in	27.56 in
M	16.1 in	27.95 in
L	17 in	28.35 in
XL	18.1 in	29.13 in
2XL	18.9 in	29.53 in

Note: Allow for a tolerance level of 1 inch

Ladies V Neck T Shirt

Size	Chest Width	Shirt Length
S	17.25 in	25.5 in
M	19.25 in	26 in
L	21.25 in	27 in
XL	23.25 in	28 in
2XL	25.25 in	28.5 in
3XL	27.25 in	29 in

Note: Allow for a tolerance level of 1 inch

Youth T Shirt

Size	Chest Width	Shirt Length	Sleeve Length
XS (4-5 years)	16 in	20.5 in	13.5 in
S (6-7 years)	17 in	22 in	14.5 in
M (8-9 years)	18 in	23.5 in	15.5 in
L (10-11 years)	19 in	25 in	16.5 in
XL (12-13 years)	20 in	26.5 in	17.5 in

Note: Allow for a tolerance level of 1 inch

Mug

Twill Cap

360 Crown	Front Crown
22.24 in	12.6 in

Visor's Length	Visor's Width
6.69 in	4.53 in

Note: Allow for a tolerance level of 1 inch

Tumbler

Cloth Face Mask

Baseball Jersey Shirt

Size	Length	Bust	Shoulder
S	29.92 in	34.65 in	14.96 in
M	30.31 in	37.8 in	16.14 in
L	30.71 in	40.94 in	17.32 in
XL	31.1 in	44.09 in	18.5 in
2XL	31.5 in	48.03 in	19.69 in
3XL	31.89 in	51.97 in	20.87 in
4XL	32.28 in	55.91 in	22.05 in
5XL	32.68 in	59.84 in	23.23 in

Note: Allow for a tolerance level of 1 inch

Basketball Jersey Tank

Size	Length	Bust
XS	27.6 in	39.2 in
S	28.4 in	40.8 in
M	29.2 in	42.4 in
L	30 in	45.6 in
XL	30.8 in	48 in
2XL	31.6 in	50.4 in
3XL	32.4 in	52.8 in
4XL	33.2 in	55.2 in
5XL	34 in	57.6 in

Note: Allow for a tolerance level of 1 inch

Basketball Suit

Size	Length	Bust	Shoulder	Pant Lengths	Waist	Hip
XS	24.8 in	36.22 in	13.39 in	18.11 in	23.62 in	38.58 in
S	25.79 in	37.8 in	13.78 in	18.9 in	25.2 in	40.16 in
M	26.77 in	39.37 in	14.17 in	19.69 in	26.77 in	41.73 in
L	27.76 in	40.94 in	14.57 in	20.47 in	28.35 in	43.31 in
XL	28.74 in	42.52 in	14.96 in	21.26 in	29.92 in	44.88 in
2XL	29.72 in	44.09 in	15.35 in	22.05 in	31.5 in	46.46 in
3XL	30.71 in	45.67 in	15.75 in	22.83 in	33.07 in	48.03 in
4XL	31.69 in	47.24 in	16.14 in	23.62 in	34.65 in	49.61 in
5XL	33.07 in	48.82 in	16.54 in	32.28 in	36.22 in	51.18 in

Note: Allow for a tolerance level of 1 inch

Hawaiian Shirt

Size	Length	Bust	Sleeve
XS	27.17 in	37.8 in	16.54 in
S	27.95 in	40.94 in	17.32 in
M	28.74 in	44.09 in	18.11 in
L	29.53 in	47.24 in	19.09 in
XL	30.31 in	50.39 in	19.88 in
2XL	31.1 in	53.54 in	20.87 in
3XL	31.89 in	56.69 in	21.65 in
4XL	32.68 in	59.84 in	22.64 in
5XL	34.25 in	62.99 in	24.02 in

Note: Allow for a tolerance level of 1 inch

This meaningful long sleeve tee blends philosophical inspiration with contemporary casual fashion. The Official Know Thyself 357 Merch Secretum Scientia Long Sleeve Tee features a thoughtful design concept that represents knowledge, reflection, and personal discovery. With a comfortable long sleeve silhouette, this piece is ideal for cooler days, relaxed outfits, or layering with modern streetwear styles. Its unique message and refined aesthetic make it a standout choice for those who appreciate apparel that combines fashion, creativity, and deeper symbolic meaning.

T Shirt:

Preshrunk t-shirt in 100% cotton.
Sport Grey: 90% US Cotton / 10% Polyester
Dark Heather: 50% US Cotton / 50% Polyester
Seamless twin needle 7/8" collar.
Taped neck and shoulders. Rolled forward shoulders for better fit.
Twin needle sleeve and bottom hems. Quarter-turned to eliminate centre crease.
Safety Green: Compliant with ANSI / ISEA 107
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Hoodie:

50% Cotton / 50% Polyester
Preshrunk fleece knit
Double-lined hood with colour-matched drawcord
Double-needle stitching at shoulder, armhole, neck, waistband and cuffs
Pouch pocket
1 x 1 rib with spandex
Air jet yarns = softer feel and reduced pilling
Tear away label
Safety Green: Compliant with ANSI / ISEA 107
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Sweatshirt:

50/50 cotton/polyester
Heather Sport colors: 60/40 polyester/cotton
1x1 rib with spandex
Air jet yarn for softer feel and reduced pilling
Double-needle stitching at shoulder, armhole, neck, waistband and cuffs
Fiber content varies by color, see color list for exceptions
Preshrunk fleece knit
Tear away label
Safety Green: Compliant with ANSI / ISEA 107
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Zip Up Hooded Sweatshirt:

Material: 50% cotton - 50% polyester; fabric material may vary depending on color and size
Preshrunk fleece knit
Unlined hood with colour-matched drawcord
Double-needle stitching at shoulder, armhole, neck, waistband and cuffs
Metal zipper
Overlapped fabric across zipper allows full front printing
Pouch pockets
1 x 1 rib with spandex
Air jet yarns = softer feel and reduced pilling
Tear away label
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Long Sleeve T Shirt:

6 oz./yd² (US) 10.1 oz./L yd (CA), 100% cotton, 18 singles
Ash Grey: 99/1 cotton/polyester
Dark Heather & Safety colors: 50/50 cotton/polyester
Sport Grey: 90/10 cotton/polyester
Safety Green: Compliant with ANSI / ISEA 107
Double-needle bottom hem
Fiber content varies by color, see color list for exceptions
Rib cuffs
Seamless double-needle 7/8" collar
Taped neck and shoulders
Tear away label
Safety Green: Compliant with ANSI / ISEA 107
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

V Neck T Shirt:

153.0 G/SqM (White 144.0 G/SqM)
100% Ring Spun Cotton
Eurofit - sleeker fit in shoulder and sleeve
Semi-fitted
High stitch density for smoother printing surface
1.6 cm mitered v-neck collar
Taped neck and shoulders
Tearaway label
Rolled forward shoulder
Twin needle sleeve and bottom hems
Quarter-turned to eliminate center crease
Safety Green: Compliant with ANSI / ISEA 107
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Tank Top:

Material: 100% cotton
Bound neck and armholes
Sideseamed
Double-needle bottom hem
Classic midweight fabric
Tear away label
Safety Green: Compliant with ANSI / ISEA 107
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Ladies Long Sleeve T Shirt:

153.0 G/SqM (White 144.0 G/SqM)
100% Ring Spun Cotton
Fitted silhouette with side seam
High stitch density for smoother printing surface
Seamless twin needle 1/2" collar
Taped neck and shoulders
Tearaway label
Twin needle sleeve and bottom hems
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Ladies T Shirt:

100% preshrunk cotton; Ash Grey 99% cotton, 1% polyester
5.3 oz/sq yd
Cap sleeves
Classic midweight fabric
Double-needle sleeve and bottom hems
Fiber content varies by color, see color list for exceptions
Preshrunk jersey knit
Seamless double-needle 1/2" collar
Sideseamed
Taped neck and shoulders
Tear away label
Safety Green: Compliant with ANSI / ISEA 107
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Ladies Hooded Sweatshirt:

Material: 52% Airlume combed and ringspun cotton, 48% polyester; fabric material may vary depending on color and size
Printing technique: DTG
Twill-taped neck; Front pouch pocket, Dyed-to-match drawcord
3-panel hood, rib-knit details at cuff hem
Colorfast; Shrink-resistant
Double-lined hood with colour-matched drawcord
Double-needle stitching at shoulder, armhole, neck, waistband and cuffs
Pouch pocket
1 x 1 rib with spandex
Air jet yarns = softer feel and reduced pilling
Tear away label

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Ladies Tank Top:

4.5-ounce, 60% combed ring-spun cotton, 40% polyester; fabric material may vary depending on color and size
Fitted silhouette with side seam
High stitch density for smoother printing surface
1 1/2" straps for S - L // 1 3/4" straps for XL 2XL
Rib knit trim applied to neckline and armholes
Tearaway label
Twin needle bottom hem
Printing technique: DTG

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Ladies V Neck T Shirt: This womens v neck t shirt fits like a well-loved favorite, featuring a modern slim fit, short sleeves and superior Airlume combed and ring-spun cotton that acts as the best blank canvas for printing. Offered in a variety of colors. Features: Sideseamed. Slim fit. Fabrication:

Solid Colors - 100% Airlume combed and ring-spun cotton, 32 single 4.2oz.
Athletic Heather - 90% Airlume combed and ring-spun cotton, 10% poly
Dark Grey Heather - 52% Airlume combed and ring-spun cotton, 48% poly

Washing Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Youth T Shirt:

100% Cotton
Seamless twin needle 3/4" collar
Taped neck and shoulders
Tearaway label
Twin needle sleeve and bottom hems
Quarter-turned to eliminate center crease
CPSIA Tracking Label Compliant

Care Instruction:

Machine wash at max. 30ºC/86ºF with short spin cycle, inside out with like colors
Do not use bleach
Do not iron
Do not dry clean
Do not tumble dry

Mug:Ceramic mug

Grip it and sip it. Personalize an mug with one of your favorite images. Full color imprinting, strong ceramic construction, and everyday convenience come together in one product.
High quality ceramic mug
Dishwasher safe
Microwave safe
Decorated with full wrap dye sublimation

Magic Mug

Ceramic mug decorated with full wrap
Graphic is revealed when hot water is added
Not dishwasher safe
Microwave safe

Twill Cap:

Our hats are available in a variety of colors and are suitable for both men and women. They provide excellent sun protection and are ideal for any outdoor activity! With adjustable snap back construction (one size fits all), everyone in your family can now wear these hats!
Add style and personality to your hat collection with a custom printed classic cap.
Constructed with 100% premium polyester that’s lightweight for maximum comfort and breathability.
Universal Fit: One size fits most with an adjustable snapback closure.
Printing technique: Sublimation

Care:

Do not bleach
Do not wash

Tumbler

Printed in the USA
Worldwide shipping
Print type: UV printing
Material: Stainless steel
Color: White background
Sizing: 12oz, 20oz, 30oz
Brand: Generic

Care:

Hand wash only with water and mild detergents
Can not be used in the dishwasher
Vibrant color reproduction
Lightweight and long-lasting
Double-wall vacuum insulation technology to keep the liquid temperature constant for several hours
Non-BPA, non-toxic

Cloth Face Mask: Constructed from a super soft polyester blend that is comfortable and won’t irritate your skin. Thickened filter material with double protection and multiple layer purification. Features adjustable ear loop buckles and an optional metal nose clip so you can find the perfect fit that suits your individual face shape. Machine wash with cold water and air dry.As this item became part of our daily lives we had to be sure that we make the best facemask possible.Our facemasks are decorated using the best and most sustainable technology in the market. Then lazer cut and sewed together -one by one- to ensure the best finishing touches.

Double Layer
Pocket for filter
Oeko-tex certificate
Eco-friendly print

4 reviews for Official Know Thyself 357 Merch Secretum Scientia Long Sleeve Tee

Rated 4 out of 5
Irene Lydia Kang (verified owner) – July 13, 2026
Such a large selection of fun shirts, great price and fast shipping! I was able to find one for everyone in my family.
Rated 4 out of 5
Penny Reid Caridwen (verified owner) – July 13, 2026
I just received my shirts in TWO days I am incredibly happy with your quickness and the beautiful shirts! I will be shopping through you again in the very near future and will recommend you to everyone I know! So very happy I found your website after hours of searching for something stylish and festive for the holidays Thank you again Super Happy 🙂
Rated 4 out of 5
Zadie Smith Henry (verified owner) – July 13, 2026
I really appreciate the customer service that was provided on my order. I was visiting in the UK and wanted to purchase a long-sleeve round neck shirt to take back to Canada as I could save on the shipping. The customer service representative was incredibly helpful in getting the package sent to my holiday accommodation in a timely manner. I wish I could get your products more easily in Canada. They are the best t-shirts I’ve ever purchased.
Rated 5 out of 5
Sarra Cannon K.L. Middleton (verified owner) – July 13, 2026
Very helpful staff, fast delivery and wonderful loyalty system.

Only logged in customers who have purchased this product may leave a review.

Production Time: All orders are processed within 2 - 4 business days. Particularly for 3D and All Over Print shirts, production time can be up to 7 business days.
Processing Time: It takes 1 - 2 days to ship your order to our warehouse, put your name and address on it and ship out.
Delivery Time: Delivery time is equal to production time plus processing time and shipping time depending on the region, country and shipping package.
Shipping Cost:
- The Standard shipping price is $4.99 (4-8 business days).
- The Ground shipping price is $10.99 (3-6 business days).
- The Fastship shipping price is $19.00 (2-4 business days).
- International shipping price is $14.99 (2-3 weeks).
- Order 2 items or $64.99 for our FREE SHIPPING (USA Only)
- Please Note: Estimated delivery time does not include production time 2-7 business days.
- Business days: From Monday to Friday excluding holidays.
Return & Exchange: If for some reasons you are not happy with your purchase, we will happily work with you to correct the problems. Items can be return/exchange and get Refund within 30 days of delivery date.
Tracking Number: When available, we will send you the tracking number with the confirmation email so that you can track the package online.
If you have problems with shipping please send to email: [email protected]