The Caddx NX416E 16 Zone Wireless Receiver Module or NX448E 48 Zone Wireless Receiver Module adds wireless capabiliies to the Caddx NetworX NX-4, NX-6, NX-8, and NX-8E control panels as well as the ELK M1 Series of Control Panels. Adding one of these receiver boards makes these control panels compatible with NX wireless transmitters and keyfobs.