I recently purchased (two weeks ago) a new Nautical SMC Super Macro Lens for use with my Canon G7x, only to find out I probably should have purchased the CMC Wet lens for this Camera. It's only been in the water once, original box and pouch but I can't use it effectively on a compact. My mistake, your gain!
Selling for $ 300 USD, new it's a lot more than that. S&H extra.
This will move fast, Will consider a trade for a CMC lens.