This is the Oceanic Pocket  Foldable Dry Top Snorkel For Diving

Features:

• Easily removed and folded for storage in BC pocket
• Dry top deflector prevents water entry
• Drop away flex mouthpiece
• Oversized purge valve for easy clearing
• Patented Snorkel Lock allows easy removal and attachment
• Replaceable 100% liquid silicone mouthpiece
• Dimensions when folded are 7″ by 4″ by 2.1/2″

A Good Diver is Always Prepared
For divers that dislike wearing a snorkel, but know that they should always be prepared, Oceanic provides an innovative solution. The Pocket Snorkel folds neatly and out of the way in your BC pocket when not in use.