Review on 3 Pack Combination Smoke and Carbon Monoxide Detector: Portable Battery Operated Fire & Co Alarm for Home and Kitchen by Robert Johnson

These alarm clocks will drain the battery in just a few days and then start shutting off with no smoke. Also, the LCD display, which is supposed to indicate safe operation, is a very, very bright strobe light that lights up the whole room like a flash. In fact, it may be the brightness of this light that explains the very fast battery drain. Don't try to buy those dangerous alarm clocks. You cannot defend yourself for long.