brand new and high quality Features: Made of high quality material, solid, durable and good performance, long service life. It adopts a natural diffusion method for detecting oxygen concentration, using high performance electrochemical sensor, with excellent sensitivity and excellent repeatability. It can effectively prevent people from hypoxia and oxygen poisoning, and ensures the safety of The staff's life is not infringed. It features embedded micro control technology, simple operation, complete functions, high reliability. Low concentration 19.5%VOL yellow warning light flashing., and high concentration 23.5%VOL red warning lights flashing, alarm concentration can also be set up. And it has sound, light and vibration alarm, you never miss it. Large LCD display, clear menu operation interface, battery power real for time display, easy to operate. Light and compact size, easy to carry and store. Perfect for explosion-proof, are widely used in metallurgy, power plant, chemical, mine, tunnel, underground pipelines or mines and other places, Oxygen Meter only, other accessories demo in the picture is not included! Specification: Powered By: 3 x AAA Batteries (Not included) Material: ABS, Electronic Components Size: app.12 x 6.5 x 2.5cm/4.72 x 2.56 x 0.98in Color: Blue Quantity: 1 Pc Product Parameters: Test Gas: Oxygen Measurement Range: 0-25%VOL Measurement Error: 2% Resolution: 0.1% Preheating Time: Less than seconds Response Time: Less than 15 seconds Environmental Temperature Measurement: -15 ~ 50 Alarm mode: Sound alarm, light alarm, vibration alarm Alarm: Low concentration 19.5%VOL yellow warning light flashing High concentration 23.5%VOL red warning lights flashing (alarm concentration can also be set up) Continuous Working Time: 6 hours (With a slight change in the working state) Audio Tip: The higher the frequency of the beep sound, the higher the concentration is. Note: No retail package. Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 x Oxygen Meter