2-in-1 cap for Nalgene, Hydro Flask, CamelBak, and other wide mouth bottles.
Small cap and smooth spout for splash-free drinking.
Big cap for fast cleaning and filling with ice, etc.
This new version has a Capkeeper which holds the lid out of the way while you drink.
This also allows you to fill your bottle from a river or lake and then use the steripen to sterilize and then you don't have to worry about accidentally drinking dirty water.