inputs.text: work without fail - bought two one store entry door already magnetic sensor installed wires running back store transmitter receiver 8 apart mistakenly wired normally closed interpreted mean door needed normally open refers switch magnet holds switch open door opens sensor separates magnet closes transmitter comes set defaulted normally open put jumper back worked fine second one use garage door 40 away brick wall bought garage door sensor another vendor hooked wide gap sensor 275 works also normally open transmitter no problems transmitting distance brick wall pleased units also glad use 9v batteries 1 cheapo door sensor used odd battery hard find