Space Age Electronics' MS Series REMOTE ACCESSORIES are designed to be used with Duct Smoke Detectors to provide audible and visual indication as well as remote test/reset functions. These devices are constructed of durable brushed stainless steel and mount on a standard single or double gang electrical backbox. Single gang cover plate designs with key operated test/reset feature standard. Compatible with RW, SM and SL Series Duct Smoke Detectors. UL listed.