Engineered base layer · Made for men 25–45
BSLYR
The structural layer beneath your shirt.
Engineered for posture and recovery. Built quietly. Worn under everything.
Shop the layer01
Smooth silhouette under any shirt
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Posture support, all day
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Recovery between sessions
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The structural layer
Built to disappear under everything you wear.
Four-way compression engineered for posture. Flat seams that sit smooth under woven shirts. Thermo-regulating fabric that breathes through the gym, the office, and the back-to-back calls between.
Refined for men who notice fit and don't talk about it.
Find your size
Sizing
Important — read before ordering
BSLYR is engineered as a structural compression layer. Size by your height and weight, not by your usual US t-shirt size. Compression fit runs ~1 size slim from standard US sizing.
| Size | Height | Weight |
|---|---|---|
| S | 5'3" – 5'5" 160–165 cm | 99–115 lb 45–52 kg |
| M | 5'5" – 5'7" 165–170 cm | 115–132 lb 52–60 kg |
| L | 5'7" – 5'9" 170–175 cm | 132–148 lb 60–67 kg |
| XL | 5'9" – 5'11" 175–180 cm | 148–165 lb 67–75 kg |
| XXL | 5'11" – 6'1" 180–185 cm | 165–192 lb 75–87 kg |
| 3XL | 6'1"+ 185+ cm | 192+ lb 87+ kg |
Between two sizes? Size up. Doesn't fit? Email [email protected] — 30-day money-back guarantee, no return needed.
Choose your layer
Shop BSLYR
Early customer feedback
The most common piece of feedback we get
"First time my polo doesn't pull weird across the chest. The layer just sits there and the rest of the day works."
— Early customer · 03/2026
"Wore it under a dress shirt for back-to-back meetings. Posture stayed up, the shirt sat right. I forgot I had it on by 3pm."
— Early customer · 04/2026
"Bought one for the gym, ended up wearing it every day. Built to disappear is the right description."
— Early customer · 04/2026
Questions
FAQ
How does it fit?
Compression fit runs ~1 size slim from standard US sizing. Size by your height and weight using the chart above, not by your usual t-shirt size. Between two sizes? Size up. The fabric stretches in four directions. Sizes S–3XL.
When will it arrive?
We ship from our manufacturing partner in 7-15 business days. You'll receive tracking once your order is dispatched, typically within 48-72 hours of purchase. Reply to your order confirmation any time for a status update.
What if it doesn't fit right?
30-day money-back guarantee. If the size isn't right or the layer doesn't work for you, email [email protected] and we'll refund the order — no return needed.
Can I wear it under a dress shirt?
Yes. The flat seams sit smooth under woven shirts. Designed specifically to disappear under polos, dress shirts, and t-shirts.
Is it machine washable?
Yes. Cold machine wash, tumble dry low. The compression structure holds up through 100+ washes.