Features:Professional for testing the oxygen content of the air, with 0-25% oxygen content detection range.Adopts with good quality electrochemical sensor, the O2 meter respond quickly yet has high precision.3.7V 1000mAh large capacity rechargeable lithium battery has long standby time and low power consumption.2.7-inch large LCD display screen, and the green backlight for clearly reading the measured data.Compact portable size with ergonomic design is easy to use, high quality rubber buttons has comfortable hand feel during operation.Sound and light dual-alarm when the measured result exceed the preset alarm value.The O2 tester has stable performance and high accuracy that suitable for home use, agriculture, chemical industry, etc.Specifications:Material: ABSVoltage: AC100-240V, 50/60HzOutput: DC5V±5%, 1000±50mAMeasuring Range: 0~25%Resolution: 0.1%Temperature: -10~50Resolution: 0.1Working Humidity: 0~95%RHPower Supply: 1 * 3.7V, 1000mAh rechargeable li-ion batteryScreen Size: 4.4 * 5.3cm / 1.73 * 2.08inStorage Box Size: 23 * 20.5 * 5cm / 9.06 * 8.07 * 1.97inItem Size: 18.3 * 6.5 * 3cm / 7.20 * 2.56 * 1.18inItem Weight: 245g / 8.64ozPackage Weight: 743g / 26.21ozPackage Size: 25.5 * 21 * 5.7cm / 10.04 * 8.27 * 2.24inPackage List:1 * Detector1 * USB Cable1 * Storage Box1 * Manual (English)