Carbon Monoxide Meter. CE mark approval. Portable and simple one hand operation. Display back light. With max/data hold function. Handheld lightweight design. Wide CO measuring range of 0 to 1000PPM. Display: 3-1/2 digit liquid crystal display (LCD) with a maximum reading of 1999. Polarity: automatic, positive implied, negative polarity indication. Zero: automatic. Low battery indication: displayed when the battery voltage drops below the operating level. Operating environment: 32 to 105 degree F (0 to 50 degree C) at greater than 75 percent relative humidity. Storage temperature: -4 to 140 degree F (-20 to 60 degree C), 0 to 80 percent R.H. with battery removed from meter. Accuracy: stated accuracy at 23 degree C (+5 degree C), greater than 75 percent relative humidity. Measures 2-5/8" width by 7-1/2" height by 1-25/64" depth. 1 year warranty.