... Accuracy; +/-3% F.S. Alarm method: light, sound and vibration Features1. Test gas in the office, workshop, train, bus, mine, mountain, vessel ... cabinet ect.2. With backlight, alarm with light vibration and ... Sensor changeable6. Automatic Temperature Compensation in full range. 7. Large test range up to 0-50000ppm or 0-100% Vol. 8 ...