The patented Big Bite(TM) Valve mouthpiece offers hands-free hydration and is ideal for any high-performance situation. Self-seals after each drink to eliminate annoying drips. FEATURES One-piece silicone design includes no moving parts to break Self-seals after each drink to eliminate annoying drips SPECIFICATIONS COLLECTION: Reservoir Parts ACTIVITY: Accessories BPA/BPS/BPF FREE: Yes MATERIAL: Medical grade silicone