Maybe I am missing something. I see that when you use the CTX 3030 in water with out headphones you cover the plug for headphones. But I noticed there is nothing to cover the exposed threads beside the plug. I heated up a 1/4 20 nylon screw and capped it with that. when I use my waterproof headphones til I get the proper size screw. just to keep the threads clean. Don Tyler Merrimack,NH