• Working voltage: DC 3.3V-5V
• Operating temperature: -10 ℃ - +50 ℃
• The 4 pins are G (GROUND), + (3-5VDC), DO(Digital Out), and AO (Analog Out).  

DO is a normally LOW output,  if a magnet is placed near it, the pin goes to HIGH state.

A0 is a normally high analog value, change if a magnet place near it to low analog value adjustable via potentiometer.