Door-magnet-170U is 100% waterproof in stainless steel execution to the compromious harsh environment. Door-magnet-170U can be used with all access control controls that have relay output. The product contains a powerful electro magnet that "locks" itself fixed to the piece of metal that is mounted on the door. When there is voltage on Door-Magnet-170U, the door cannot be opened. An access control connected to Door-Magnet-170U accepts eg. A password will interrupt the voltage of the magnetic coil and the magnet drops so that the door can be opened. Holding power: 136 kg. 24VDC voltage to the holding magnet.