Magnetic contact via bidirectional radio, frequency 868Mhz. EN50131 Grade 2 Certificate. The RWX73M Bidirectional Wireless Door / Window Magnetic Contact is a supervised transmitter ideal for the wireless protection of doors / windows in residential applications and in small businesses. The transmitter has a built-in magnetic contact and an additional zone input, to which other magnetic contacts or wired detectors can be connected, which can be used for different control or safety applications. CR123 3V lithium battery included. Compatible with RISCO™ Agility 3 system.