Carbon monoxide meter detects the presence of carbon monoxide co and measures concentrations between 1~1000 parts per million ppm . The meter indicates the presence of co by a reading on the lcd and a beeper tone. The beeper function much like the clicking of a geiger counter above 200 ppm, The ppm the beeper sounds continuously with the concentration of co. From pinto 200 ppm. The beeper sounds discountinuously with the concentration of co. Specifications initial measurement range is zero to 1000 ppm resolution 1 ppm accuracy 5% warm up time 2 sec. Sensor type electrochemical operating temp. 0 up to 50 degrees Celsius dimension 160 x 56 40 millimeters weight 180 g