There are two modes with the Alcosense Pro
  1. Normal mode (nor) - provides you with a BAC% reading e.g. 0.04% 
  2. Fast mode (FSR) - a quick test to show whether alcohol is detected. Result will be shown as a "fail" or a "pass"
You can change between these two modes: 
  1. While the unit is switch off, hold down the power button
  2. The screen should begin to flash between "modes" while the button is held down
  3. Continue to hold down the button until the mode of your choice flashes on the screen
  4. For Normal mode = "nor" or Fast mode = "Fsr"
  5. Release the power button once the mode of your choice flashes on the screen