Our water bag manufactured of microban anti-bacteria material, the smoothness of the liner prevents the germ and the lime from adhension, which promotes health. It's simple to drink, pull the rubber mouth piece out and the water comes right out. Push rubber mouth piece back to close, You don't have to bite anything. Our water bladders passed pneumatic pressure test, 24 hour swing test and 24 hour vibration test. It is completely pressure-tolerant and leak proof for carefree biking, running, hiking and other outdoor adventures. Durable and soft anti-microbial mouthpiece for wholesome and effortless sipping. Easy to bite with 90-degree turn mouthpiece. Easily accessible shutoff valve.