Wireless Contact Sensor (MCT-340 SMA)
https://csa-iot.org/csa_product/wireless-contact-sensor-mct-340-sma/
…message will be sent to the receiver 30 days before expiration of battery life Specifications: WIRELESS Supported Network: ZigBee Home Automation 1.2 Frequency: 2.4 GHz as per IEEE 802.15.4 Tamper…