Kidde KN-COSM-BA Battery-Operated Combination Carbon Monoxide and Smoke Alarm with Talking Alarm , WHITETalking alarm announces the hazard type detected, helping to speed up reaction time A single unit can be installed where previously two were needed Battery safeguard ensures the unit cannot be accidentally mounted without batteries installed Test reset button tests alarm circuitry and triggers the voice announcement Meets requirements of Underwriters Laboratories (UL), an independent facility that tests products for safety compliance