The Calibration Certificate can only be ordered with the AELP/PT/PTS. It provides information about the machine's performance and accuracy. Generally, it's a requirement of any company with ISO Quality systems in place where a record of the scale's calibration needs to be kept by the user. Please note: we can not issue calibration certificates to scales previously supplied that did not include a certificate in the order. These certificates do not make the scale or balance Trade Approved.