Most people love the convenience of the wide mouth bottle when it comes to filling & cleaning but sometimes find it hard to drink from. The Easy Sipper solves that problem. It fits snugly into the neck of the bottle & your beverage flows out in a nice controlled flow. It's then easy to pop the Easy Sipper out to clean or fill your bottle. Dishwasher safe. Fits 32oz Wide Mouth Nalgene bottles only.