What Our Gearhead(R) Experts Are Saying:"I like this for gym sessions and warm crag days. The heavier organic cotton feels substantial without being stiff, and the relaxed cut gives full freedom through the shoulders when reaching overhead."When the sun hits the rock and the session stretches into the afternoon, we reach for simple layers that let us move freely. The Black Diamond Project Muscle Tank is built for climbing gyms, crag days, and training sessions where comfort and durability matter most. Made from heavyweight organic cotton, it delivers a soft yet sturdy feel that holds up to repeated wear. The relaxed fit and open arm design provide unrestricted shoulder movement for dynamic moves and overhead reaches. Breathable and straightforward, it's equally at home during hangboard sessions, approach hikes, or post-climb hangs. With organic cotton certified for reduced environmental impact, this tank combines everyday comfort with conscious construction.