THANKS FOR LOOKING AT MY ADD WHAT I HAVE FOR SALE IS A KIDDE CO ALARM PLUG-IN WITH BATTERY BACKUP. TAMPER RESIST ALARMS WHEN REMOVED FROM THE WALL IMPORTANT FEATURES: 120V AC POWER PLUGS DIRECTLY INTO AN EXISTING AC WALL OUTLET. BATTERY BACK UP ALARM PROVIDES DETECTION EVEN DURING A POWER OUTAGE. TEST/RESET BUTTON ALLOWS YOU TO IMMEDIATELY SILENCE ALARM AND TEST ALARM ELECTRONICS. TAMPER RESISTANT FEATURE UNIT ALARMS WHEN REMOVED FROM WALL OUTLET. LOUD 85 DECIBEL ALARM. OPEN BOX UNIT IS BRAND-NEW NEVER BEEN PLUGED IN. PLEASE SEE PICTURE'S FOR DETAILS. THANKS.