You've already got the water bottle, now you just need the clean water. The DayCap In-Bottle Filter seamlessly fits onto three popular wide-mouth water bottles-Nalgene(R), Hydro Flask(R), and Yeti(R) Yonder(TM)-and transforms them into fast, safe and incredibly easy water filters. The removable filter utilizes the same hollow fiber technology as our award-winning backpacking filter systems to filter water safely and quickly. By only lightly pulling water through the spout, the speed of the filter allows you to drink as you normally would from your bottle. If the flow begins to slow down, simply shake your bottle with the DayCap and filter attached to clean it and restore the flow rate. Made of premium materials, the cap is durable, and features a sturdy loop for secure hanging and carrying. The spout is shaped to optimize flow and provide a natural drink experience. It has a flip-up leak-free cover that stays out of the way when you're drinking. In cap-only mode, the DayCap works as a perfect everyday cap for your bottle when you're not on the trail. With the filter on, whether it's a day hike or a backpacking trip, the DayCap In-Bottle Filter makes worry-free hydration as easy as scooping and drinking.