I am looking for some limit switches for an underwater application. They need to withstand continuous immersion in fresh water at a depth of 6-7 feet. I need NC contacts, for operation at 24VAC.

Cutler-Hammer has their E50 6P+ series, which are rated NEMA 6P/IP67, but for continuous immersion, I really think I need an IP68 rating. Does anyone know of a source for these?