Seaflo SFBS-30-01 BOAT BILGE PUMP SWITCH (12V, 24V, 32V) Long life, switching frequency up to 10 million times;Ultrasonic welding, forming a seal, reliable and secure, not leaking Turn pump on when water level reaches 2 (51mm) ; Turn pump off when water level reaches 3/4(19mm) Shells made of high quality ABS material, the internal metal contacts to ensure reliable start / stop; Ideal flow sensor for bilge pumps Latest design includes a removable base for easy cleaning and servicing Heavy duty flow switch is designed for the toughest applications; Environmentally responsible.