Model KN-COB-B (P/N 9CO5). Test/Retest Button - Tests unit and silences alarms. Easy-to-Install - No wiring required. Protect your family from the silent killer! This Carbon Monoxide Alarm provides protection for general use. Alarm Benefits: Battery operated alarm provides protection even during a power outage. Test/Retest button allows you to immediately silence alarm and test alarm electronics. No costly sensor replacement needed. Loud 85 decibel alarm. Make Sure Your Entire Home is Safe: Kidde, the world's leading manufactured of home safety products, offers a complete product line to protect your home and family. Common Sources of Carbon Monoxide: Cars left running in attached garage; Clogged chimney; Corroded or disconnected water heater vent pipe; Gas or woodburning fireplace; Cracked or loose furnace exchanger; Improperly installed kitchen range or vent; Operating a grill indoors or in garage; Portable kerosene or gas heaters. Carbon Monoxide Alarm Response Times - This Kidde Carbon Monoxide Alarm meets response time requirements of UL Standard 2034 which are as follows: At 70 ppm, unit must alarm within 60-240 minutes. At 150 ppm, unit must alarm within 10-50 minutes. At 400 ppm, unit must alarm within 4-15 minutes. UL Listed. Custom assembled in China. 5 Year Warranty.