Brooks Atmosphere Singlet Men's For athletes who test their limits, the Brooks Atmosphere Singlet works as hard as you do to reach your goals. DriLayer® fabric wicks sweat more efficiently to keep you cool and focused during your runs. If you're looking for a lightweight layer that minimizes distractions, the Brooks Atmosphere Singlet helps you max out the mileage! Technical DriLayer® fabric is engineered to minimize sweat for distraction-free miles. Anti-microbial finish keeps the top fresh between washes. Made with 100% recycled materials to reduce environmental impact. Hanger loop Minimal seaming and bonding at the back for optimal movement. Made with recycled fabric equal to 12 plastic water bottles Sizing Small: 35-37" chest Medium: 37-39" chest Large: 40-42" chest X-Large: 43-45" chest *Measurements refer to body size, not garment size.