Hassle free, 10-year, slim style Combination Smoke/Fire & Carbon Monoxide Alarm. Itâ€™s protection at its Âfinest. The PC910 alarm adds an element of style to safety. A fraction of the size of a standard alarm with all the protection needed to keep what matters most safe and secure. Alarm includes a 10 year battery to cut down on hassle and costly battery and alarm replacements.