Question about Ace AF33

This is specified directly by the manufacturer with regard to calibration: ACE recommends calibration of the sensor built into the instrument approximately every 12 months or after approximately 500 tests with the instrument. Calibration is not mandatory, the accuracy of the AF-33 built into the ACE AF-33 must be maintained. The accuracy of the sensor decreases continuously without calibration. Send the unit with the suffix "Alkomat Calibration Service" to the company address provided with the unit if this happens.