Five Oceans Automatic Boat Bilge Pump Float Switch Mercury-Free, 20 Amps FO-3610 THIS FLOAT SWITCH is mercury free and is compatible with most 12V and 24V bilge pumps Heavy-Duty Switch for bilge pumps (20 Amps Max) TURNS pump ON when the water level reaches 2" (51mm) CONSTRUCTED from high-grade marine plastic and featuring a larger float for increased buoyancy to reduce on/off cycling DIMENSIONS are 5 1/8" (130 mm) x 1 23/32" (44 mm) x 2 1/8" (54 mm)