With a discreet tone, the wireless continuity detector informs you when a person enters the monitored area. Use the volume selector switch to set the desired volume up to 90 dBA on the receiver or turn the sound off completely if necessary, then the built-in signal light in the receiver ensures that you really do not miss a thing. 8 different ringtones in CD sound quality are available. The monitoring range of 360° can be reduced to 110° by means of 3 different detection limiter caps in order to be able to monitor different areas specifically. Due to the integrated battery pack (3 AA NiMH batteries 3.7 V), the radio receiver can also be used easily and conveniently for mobile applications. To charge the battery, simply unfold the mains adapter and connect it to a 230 V socket. The transmitter with PIR sensor is battery operated and requires 2 x 1.5V Mignon batteries. Radio frequency 434 MHz. The set can optionally be extended to a radio doorbell system, see accessories.