Carbon Monoxide Detector [ 1230-NHDELUX] Rated # 1 for features, quality and value. Digital readout from 0-999 PPM confirms CO at all levels. Updated digital reading every 21/ 2 minutes, 85 decible alarm, test and reset button. Long life, state-of-the-art sensor never needs replacing. Never needs recalibration. Full 5 year warranty. UL listed. Direct AC Plug-In. Hub : Mia 0856 9139 8333