Which item is typically specified in manuals for calibration after service?

• A. The color of the calibration sticker
• B. The warranty terms related to calibration
• C. The last calibration date of the equipment
• D. The required calibration procedures and reference instruments to be used

Answer: (D)

Calibrating after service relies on following defined procedures and using the specified reference instruments. Manuals lay out exactly how to perform calibration, including the steps to take, the instruments or standards to use for comparison, and the acceptable tolerance or criteria for passing. This ensures measurements are consistent, traceable to recognized standards, and the equipment remains compliant after maintenance. The other items don’t establish how to perform calibration: the color of a sticker is cosmetic, warranty terms cover protection rather than the calibration method, and the last calibration date is a record of history rather than a specification guiding the calibration process itself. In practice, you’ll see in the manual the calibration steps, reference instruments, and criteria—that’s why the required calibration procedures and reference instruments to be used is the best answer.