1. High-precision and high-stability electrochemistry, specific CO sensor detects CO in the air with high precision and 0-999ppm detection range. 2. 1.1-inch high-definition large screen shows the numerical concentration value, red backlight and buzzer alerts, emitting intelligent circular alarm with drip sound to prevent danger. 3. High-strength plastic shell is tough and wear-resistant. 4. The rear cover is detachable to facilitate battery replacement. Powered by 2x1.5V AAA batteries (not included). 5. Suitable for detecting carbon monoxide gas and finding of leakage in places with carbon monoxide gas, fog and residues, and is suitable for homes, kitchens, cars, restaurants, indoor places and so on. Display Screen: LCD with backlight Sensor: low power consumption electrochemical sensor Detection Range: 0~999PPM Response Sensitivity: Less than 50PPM Response Time: 2s Alarm Mode: numerical value, red backlight and buzzer Data Retention: On-Off Test: Power Supply: 2x1.5V AAA battery (not included) Service Environment: 0~50/20%~80%RH without explosion-proof conditions Storage Environment: -10~60/20%~80%RH Colour:black Material:plastic Package Contents: 1 x Carbon Monoxide Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.