Mazama Designs Bite Valve Conversion Kit with Bite Valve or Open Flow, Fits Most Hydration Packs and Bladders Innovative new valve offers bite valve or open flow; Compatible with Most Hydration Packs Open flow mode allows optional continuous fluid delivery and ensures drink tube can be fully air dried after reservoir use Simply twist sheath for open flow Articulating shut-off allows right or left bite valve positioning Quick release connector allows bladder fill-up without removing drink tube from your pack strap