I am using a couple MH-57s with my VX-7R HTs and get good reports. They are not waterproof/submersible.
The MH-57s also have a jack for an external speaker which sounds surprisingly good. Before I got my FT-8900 installed mobile, I used one of the VX-7Rs, the MH-57, an old Johnson external speaker and an RF Concepts amp/pre-amp. It worked so well, it was easy to forget the rig was just cobbled together. In the dark, it seemed just like a real radio.