These normally open pump switches operate by a magnetic reed control switch. They are self-cleaning with a clog-proof design. No timer delays, no electronics or mercury. They are impervious to all materials commonly found in bilges. Switch components are completely sealed against moisture. UPS-01 & UPS-02 are the same except UPS-01 series is alarm ready with an attached sensor for use with A201R optional high water alarm (sold separately). UPS-06 is the same as the UPS-02 series except it’s smaller and NOT alarm ready. Maximum Amps for all: 20. *Normally closed switches available on spe