This sensor detects the alarm sounds of virtually all your audio, smoke, gas and fire alarms - even the new alarms with T3 or T4 type alarm sounds - and sends a wireless signal to trigger the CentralAlert CA-360 notification system to alert you. Install it next to your existing alarms for sound detection or connect it directly to your alarms for activation. Note: This item will not work on its own. It is an option for use for the CentralAlert CA-360 notification system (available for purchase separately). FEATURES & SPECIFICATIONS: - Mount it next to your audio alarms for alarm sound detection. It is the only sensor that will respond to all alarm sounds, including those alarms with T3 or T4 type sounds. - Can also be hardwired to your audio alarms that come with connecting terminals for direct activation. - Sends a wireless signal to activate the CA360 to alert you. - Battery powered (batteries not included) with low battery indicator - Advanced Technology: 2.4 Ghz Smart-Code - Operating range: Up to 200ft, open space - actual distance varies according to house construction - Up to 10 Model CA-AX's are supported by a system - Battery type: Two AA size alkaline - Battery life: up to 10 months Product Dimensions: 2.5" x 3.8" x 1" Weight: 2 oz.