Are you implying a waterproof case for the Fox 40 whistle?

When I am out in the canoe, the whistle is always securely attached to my PFD as the last thing I want to worry about is rummaging through gear looking for a whistle to hopefully attract the attention of other boaters close by, especially in colder weather and water where your life expectantly can be measured down to minutes. With the carabiner attached, there is enough length in it and the attachment point for the whistle to be used hands free once you place it in the mouth with no worry of losing it if accidentally released from the mouth.

As a side note. Our provincial .gov freely hands out 1000's of these Fox 40 whistles every year. Needless to say, I have a lifetime supply of these whistles stashed everywhere.