Kidde 0915D-018 Battery-Operated Basic Smoke Alarm with Low Battery Indicator, Twin Pack Test button and LED allows simple verification of battery and alarm operation Warning chirp sounds when smoke alarm battery needs replacement Loud 85 decibel alarm alerts you of danger Tamper resist pin inhabits tampering of smoke alarm Kiddes wireless smoke alarms meet the requirements of Underwriters Laboratories (UL), an independent facility that tests products for compliance with widely-accepted safety standards