An OTA Favorite!! Hands down the best defogger we've ever used.  It's thick but rinses easily and never burns your eyes.  Best of all, you've got a nice, clear view of the aquatic environment. 

500 PSI Mask Defog is without question the clearest, longest acting and most effective defog on the market. One application works for at least three dives in one day. Cleans your mask each time you use it. Wet or dry application, has the consistency of extra thick toothpaste, and when applied to the lens typically lasts all day long. 500-PSI Mask Defog comes in a 2oz squeezable bottle with a convenient carabiner clip to attach it to your favorite dive bag, so you never hit the seas without it!

 Specs:

500-PSI Mask Defog Features

• 500-PSI Mask Defog
• De-Fogs Sports Lenses
• Great for Snorkel or Dive Masks
• Clearest Longest Acting Defogger
• One Application/Three Dives
• Cleans Lens Each Time
• Wet or Dry Application
• Applicator: Spray Bottle
• Content: 2 or 4 fl. oz. (59 or 118 ml)
• 2 fl. oz. (59 ml) Available with Carabiner Clip