A float switch is a device used to sense the level of liquid within a tank. The switch may actuate a pump, an indicator, an alarm, or other device. It can be easily converted from normally open to normally close by inverting the float. Note: because the current that the switch can carry is much little(0.5A), you must use a relay or contactor when it is connected by a load, relay or contactor are not included here. Product Name: Water Level Sensor; Model No.: ZP4510-S; Contacts: NO+NC; Max Contact Rating: 10W Max Switching Voltage: 100V DC; Max Switching Current: 0.5A; Max Breakdown Voltage: 220V DC; Max Carry Current: 1.0A; Max Contact Resistance: 100mΩ Temperature Rating: -30 - +125C; Float Ball Material: SUS304; Float Body Material: SUS304; Float Ball Size(Approx): 26 x 26mm / 1.02 inch x 1.02 inch(L x D); Thread Dia(Approx): 9.8mm / 0.386 inch Bottom Clip Dia(Approx): 14.7mm / 0.579 inch; Hex Nut Size(Approx): 16.6mm / 0.654 inch; Body Total Length(Approx): 62mm / 2.4 inch Cable Length: 31cm / 12.2 inch; Color: Silver Tone; Net Weight: 390g; Package Contents: 10 x Water Level Sensor Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.