SR4P3-A1 - 

Honeywell SR4 Hall-Effect Sensor
The Honeywell SR4 series hall-effect position sensors come in a sealed threaded housing. They respond to the magnetic field of permanently positioned magnets or electromagnets, responding to either an alternating north or South Pole or to South Pole only. A wide variety of digital unipolar, latching, and linear magnetic types are available in a number of sensitivities depending on the application requirements. They can easily be easily interfaced with common electronic circuitry such as microprocessors, integrated logic, diskrete transistors, and SCRs with compatible voltage specifications.