"Always on" technology ensures the sensor is monitored around the clock, whether your system is armed or not Ultra sensitive smoke sensor prevents false alarms while constantly monitoring Heat sensor detects the rapid rise in heat that comes from a fire – even when there is no smoke (like an electrical fire) Wall or ceiling mounted 3-5 year battery life The detector has a built-in wireless transmitter, which communicates with the control panel. When smoke is detected, the alarm sounds a loud local alarm and the built-in transmitter sends a signal to the control panel. The Alarm contains an integrated fixed 135°F temperature sensor that will send a warning signal based on temperature detected. This detector is designed to provide protection with 70-foot spacing capability. The detector can send alarm, tamper and battery condition messages to the system's receiver.