Always verify that all sensors present in the instrument are shown on the current gas readings screen whenever the IQ Force is turned on. Failure to verify sensor presence prior to use in ab bhazardous location may result in serious injury or death. The battery icon gives an indication of how much power is left in the battery. The illustration below shows the stages of the battery from full to empty top to bottom). Battery charge greater than Battery charge between 50% and Battery charge between 25% and Battery charge less than To turn on the backlight press the MODE button once. To view the MAX readings screen, press the MODE button a second time. Press the MODE button a third time to view the Short Term Exposure Limit (STEL) readings. Press the MODE button again to view the Time Weighted Averages (TWA) for the operating session.