The DPM-500 by CDVI is an ideal solution for auto-relock control on 500kg surface maglocks and saves the need of fitting door contacts. When installed alongside a electro-magnetic lock, the DPM-500 ensures reliable door position monitoring. It is an ideal solution for auto-relock control and saves the expense and time fitting door contacts. This model is for use with surface mount 500kg maglocks only. Accurately monitors the door position Retrofits to surface magnetic locks Saves time & expense of fitting door contacts 1x NO/NC changeover contact Compatible with 500kg surface mount maglocks For other options see DPM-400 (400kg maglocks) or DPM-300 (300kg maglocks)