The Standard Digital Grey Kard model DGK-1 is a calibrated and tested white balance card / digital color correction tool for digital photography. The DGK-1 consists of three calibrated color reference cards, both sides matte finish and spectrally neutral. Each card measures 2" x 3 1/4" or approximately 50 by 83 millimeters. Easy to follow instructions and a convenient carry lanyard with detachable clip are included.