Sugoi Zap Arm Sleeves The ultimate in visibility The Sugoi Zap Arm Sleeves bring visibility and lightweight warmth to your favorite shoulder-season rides. The Zap Arm Sleeves use Fino Stretch fabric, with a supportive, high-stretch design that's combined with MAB(R) Power Band silicone grippers to keep the sleeves in place over the longest days on the bike. But the most striking feature of these sleeves is the Zap Tech visibility, a series of micro-glass lenses that-when viewed with direct light-light up like the Aurora Borealis while being almost invisible during the day. The Zap Arm Sleeves keep you visible and shield you from cool temperatures, letting you ride with confidence. Features Fino Stretch fabric moves with you for impressive comfort MAB(R) Power Band silicone gripper keeps the sleeves comfortably in place without binding Zap Techuses highly reflective micro-glass lenses to create impressive visibility at night, while being nearly invisible during the day Sizing Size XSSmall Medium Large XLBiceps Diameter (IN)10 - 11"11 - 12"12 - 13"13 - 14. 5"14. 5 - 16Biceps Diameter (CM)25. 5 - 28cm28 - 30. 5cm30. 5 - 33cm33 - 36. 5cm36. 5 - 40. 5cm | Sugoi | Zap Arm Sleeves Men's | Size Large In Black