This product is part of the NEMA Pressure Switches range, an offer of mechanical alternators. This mechanical alternator has 4 normally closed, snap action, DPST-DB (double pole single throw, double break) form YY contacts. The closed tank mechanical alternator supports screw-in bush mounting method and 90 (offset) float rod angle for operating in left position. Mechanical alternator is used in applications where the water level change is 4.75 inches minimum and 9.25 inches maximum. It is furnished with screw clamp terminals for electrical connection and 2 conduit entries for 3/4-14 NPT. Offers electrical durability of 100 cycles and mechanical durability of 300 cycles. The enclosure is made of cast aluminum. It weighs 22.2lb. It is a NEMA 7&9 rated product. This product is certified by UL, CSA, CE. Meets UL 508 standards. When liquid level rises to the first level, one pump turns on. Both pumps automatically turn on when a peak condition occurs and the liquid level continues to rise. If form N5 or N25 is present and the water level continues to rise. Mechanical alternator provides a simple, positive means of mechanically alternating two pumps or motors. This alternator is used on devices that are installed in a duplex system with a common tank. The kit includes float switch, float and rod. A complete line of switches designed for open or closed tank applications they detect rising or falling liquid levels in various types of containers. The Square D brand water pressure switch has expanded to industry leading Pressure Sensors and Switches.