Which of the following is NOT a type of calibration sticker mentioned?

The term "Prototype Calibration" is not recognized as a standard type of calibration sticker within the context of aviation maintenance or equipment calibration processes. Calibration stickers serve vital purposes in ensuring that equipment is functioning correctly and safely.

The white sticker indicates that the equipment is in a calibrated state, having passed necessary tests. The yellow sticker denotes special calibration, which is typically used for equipment that requires more frequent checks due to its specific operational demands. The red sticker signals a rejected calibration, indicating that the equipment has failed its calibration and should not be used until issues are resolved.

Since "Prototype Calibration" is not an established category associated with calibration stickers, this option stands out as incorrect. Understanding the standard calibration classifications is crucial for maintaining operational readiness and safety in aviation environments.