Short sleeves have become a common feature with pro triathletes. Sleeves provide sun protection, comfort, and in the case of the Free Speed 2 Race Top improved aerodynamics. Through its relationship with Norwegian Technical University in Trondheim, Castelli has created one of the slickest tri tops there is with the aerodynamic sleeves and Velocity Rev2 fabric on all front facing surfaces.   The Speed 2 Race Top allows freedom of movement in the water and comfort on the run. Reduced seaming lessens chaffing, and the mesh fabric back blocks 94% of UV light. A SnapLock fastener at the lower back clips to the Castelli Free Tri Short to prevent riding up during the swim or cycle.   Features Freedom of movement in the water, aerodynamics on the bike, comfort on the run. Suitable for all triathlon distances. Velocity Rev2 aero fabric on front-facing surfaces. Velocity mesh fabric blocks 94% of UV light. 2 rear pockets lie flat. Giro3 flat gripper lies flat on lower back. SnapLock fastener at lower back to clip to Free Tri Short. YKK Camlock zipper. Elbow length sleeves for aerodynamics. Weight 174g (Large).