Vivint VS-DW2100-345 wireless door/window contact sensor
Vivint VS-DW2100-345 Wireless Recessed Door/Window Contact Sensor, designed to be installed flush inside a door or window frame for discreet monitoring. -Magnetic contact sensor that sits inside the door or window frame for a hidden appearance. -Wireless sensor operating on a 345 MHz frequency. -Works seamlessly with Vivint Smart Home systems. -Features a wireless signal range of approximately 700 ft (213 m) in open air.