I bought two Kidde P19010 Battery Operated Dual Ionization and Photoelectric Sensor Smoke Alarms last year (2012). They were for my rental house bedrooms as I had to comply with a new city ordinance. Well to my dismay they both failed between 6-7 months after their installation.After reading reviews of this product it looks like others are having this same problem. I will have to find a suitable replacement, don't buy this product.