Mercury free. Patent Pending snap switch design tested to cover one million cycles. Abrasion resistant marine grade "blocked" wire. Push button, removable base for easy installation and cleaning (Models 35A & 37A). Exclusive Rule moisture tight seals and grommet. 2 year Warranty on Rule-A-Matic and Rule-A-Matic Plus, and 5 years on Super Switch. For use with pumps drawing up to 14 amps.