TECHNOLOGY: Padded air mesh back panel for a comfortable fit FEATURES: 1.5liters or 50 fl oz. Hydration pack Great for all bike rides Lets them stay hydrated while on the move Crux(TM) Reservoir with standard exit port: offers 20% more water with every sip, easy on/off lever, Big Bite(TM) Valve, HydroGuard(TM) technology, ergonomic handle, and leak-proof cap BPA/BPS/BPF Free Stretch overflow storage for extra items and gear 3 Exterior pockets for plenty storage Mesh shoulder straps to keep cool Safety whistle in sternum strap for added safety Reflective strips increase visibility