I'm afraid I don't understand that. I understand our bilge-pump switch is nothing more than a magnet and a reed, no caps, and it just needs occasional checking that the arm moves. Don't ask how old it is, but ti works just like it is supposed to. You can get these little float switches for about a dollar on eBay. A float donut slides up a shaft, again magnet and reed - all well-sealed. They come in a variety of styles and lengths. Buy two and install in parallel.