The GRI 4110/4482 Series is basically a “vane” switch for use on storage units with overhead doors and latch type locks. Intended to be mounted on a roll up type door channel, the GRI Vane Switches will not allow the alarm system to arm unless the bolt or latch, which serves as a “shunt” between the reed switch and magnet, is in a locked position. Removal or tampering of the bolt or latch removes the shunting effect and an alarm will be activated when the circuit is opened