ColorChecker Mini Gray Balance card is a pocket size version of the 18% Gray reference square used in the standard 24-patch ColorChecker. This Gray is scientifically engineered to provide a precise uniform surface that is spectrally neutral (reflects equal amounts of red, blue and green) in all types of light conditions. The photographer can now have confidence that the camera’s raw image is as close to real life as possible.
ColorChecker Mini Gray Balance gives photographers a way to adjust the digital camera's color sensitivity to exactly match the ambient lighting conditions, in effect, change what that the camera “sees.” The perceived color of white often changes based on ambient conditions - outdoor it is perceived to be cooler, indoor it is perceived to be warmer and under fluorescent light it is perceived to be greener. Even in a controlled studio environment, establishing an accurate custom white balance ensures an accurate image from the start of each new photo session.
ColorChecker Mini Gray Balance Features and Benefits:

Pocket size version of the middle gray reference square from the ColorChecker
Provides a precise uniform surface that is spectrally neutral under all lighting conditions
Ensures that the digital camera’s raw image accurately portrays real life

Available in one size:
ColorChecker Mini Grey Balance 4" x 6"