The Fourth Element Dry Snorkel has a splash proof top, but also a small float internally, which, when the snorkel is submerged floats to the top and blocks entry of water. 

It also features a collection chamber at the bottom collecting any water that does enter allowing you to still breath and an easy one way purge valve that clears water on every exhale. 

The Dry snorkel has a soft silicone mouthpiece suitable for long use and detachable snorkel keeper.