I always carry 3 of these in the breast pocket of my vest. They are submersible, but I carry them in a ziplock just in case. Heed the dates on them. We fire our out of date flares at a 'Coast Guard Day' and have about a 40% failure rate. Remember, smoke doesn't work well at night.

When I'm sailing big boats offshore, I throw a few in my foulie pocket, just in case.