This device can function either as an alarm hub to pair with door/window sensors, motion detectors, or remote controls, or as a siren to integrate with an existing 433MHz alarm system. It supports up to 20 wireless 433MHz sensors and 20 remote controls per defense zone. The product features a unique, easy-to-install design. It cannot operate alone and must work in conjunction with a 433MHz alarm host (such as the PN-103, PG101-PG106 GSM WiFi alarm system) or with 433MHz 1527‑code door/motion sensors or remotes (not included). While suitable for outdoor use, it must be installed under shelter as it is not waterproof.