The YoLink Power Fail Alarm is a smart power monitoring sensor, that monitors 120VAC, USB power other AC voltages. With 24/7 heartbeat supervision, the Power Fail Alarm will notify you of the loss of power at the connected outlet, via phone app push notification, email, SMS, paired or automated siren or other output device (relays, etc.) as we as via SpeakerHub broadcasts (speaker plays tones, sounds and spoke messages) Monitor AC Power Status Remotely: using the free, no subscription-required and user-friendly YoLink app, you will know the AC power status, from anywhere, at any time Know Now! Receive notifications per your requirements: smartphone push notifications, email, text*, optional automated calls, and optional central station monitoring notification. Also, activate a local siren or broadcast an audio message from one or more SpeakerHubs Alarm Options: 1) Power Fail Alarm has a 110 dB sounder and four bright LED lights that activate on loss of power. 2) Patented Control-D2D device-to-device pairing, pair the PFA to one or more Siren Alarms (also with 1/4 mile range). 3) SpeakerHub can broadcast sounds/tones and voice messages via speaker (requires internet connection) Features & Benefits Three user-selected sound level settings (100, 104, 110db) Four alarm and status LEDs USB cable-powered, with optional battery operation (Two standard alkaline AA batteries) Portable; may be placed anywhere in your home or wall-mounted YoLink Control-D2D device-to-device pairing (offline mode) allows for the Power Fail Alarm to directly control other YoLink devices, without an internet connection YoLink’s industry-leading long range communication allows for operation in larger homes and in areas difficult for other wireless systems, such as basements, separate garages/structures, and even outside your home Applications Sump pump power supervision Freezer/fridge power supervision Home medical equipment power supervision Pet care-related, fish tank, etc. power supervision For technical specs and additional information, please visit the product page.