FMM-1 is a standard-sized module (typically mounts to a 4" [10.16 cm] square box) that supervises either a Class A (Style D) or Class B (Style B) circuit of dry-contact input devices.
The SpectrAlert Advance PC2RHK is a red, two-wire, ceiling-mount, outdoor horn strobe with selectable high-candela strobe settings of 135, 150, 177 and 185 cd. Outdoor back box included.