You have tried a lot of masks, and none of them seem to give you the proper seal you are looking for. Not getting the proper seal from your dive mask can be real annoying and can be on-safe when diving! This product may just be the thing you need to start really enjoying your dives. You invested a lot of money in all that gear so let's have fun with it. All purpose sealant stops mask leaks, Excellent for Mustaches. Mask Seal is a great item for your Save-A-Dive Kit.