... safety device 1)Unit:ppm, mA, %,%LEL,%VOL 2)Display:backlight LCD, LED 3)Humidity: 10-95%RH (non condensing) Gas ... and easy installation and maintenance. * Multi-parameter backlight LCD display: measuring range,digital gas reading ,units, bar graph , system status etc ... monitoring and indicating.* Programmable alarm operation value, low or high level alarm indication.* Three-key operation for on-site ...