The 2GIG DW10-345 Thin Wireless Door/Window Contact Sensor 20-Pack (GG-DW10345K2) offers an economical and efficient solution for large-scale residential or light commercial security installations. This bulk pack contains twenty individual DW10-345 sensors, each featuring an ultra-thin, 3/4-inch low-profile (0.49" deep) white housing that blends discreetly with any decor.Each sensor operates on a fully supervised 345 MHz wireless frequency, ensuring reliable communication with compatible 2GIG security panels (including legacy and eSeries models) and providing alerts for tampering and low-battery conditions. The versatile dual-zone capability of each sensor, with an internal magnetic reed switch and an external normally-closed (NC) dry contact input, allows for flexible monitoring of multiple points if needed.Powered by a single long-life CR2032 lithium battery per sensor, the DW10-345 offers up to 5 years of maintenance-free operation. These sensors are ETL-listed to UL burglary standards, guaranteeing professional-grade reliability. The 20-pack format simplifies inventory management and deployment for installers.