With the new requirements for annual inspections of fire listed door assemblies, you want to make sure that if you are installing an alarm contact into a door and frame, that the contact you install is UL Listed for field installation into listed doors and frames. 

Marray's patented HDPS (hidden door position switch) is revolutionary in design and simplicity itself to install. We have supplied these hidden switches to numorous government agencies where low key monitoring with vandal resistance is required. 

Available in several finishes and is very hard to distinguish from a real screw head. Simple to install and best of all, UL Listed 10C for fire rated frames and doors.