3 in 1 Pocket-Size Digital White Black Grey Balance Cards 18% Gray Card with Neck Strap for Digital Photography The neck strap with quick-release buckle on the end, convenient for your use. It helps you get correct white balance, or color balance, allowing the camera to compensate for the illuminant color in a scene. the black card achieves truly deep blacks ( 16,16,15); the grey card displays superior spectral neutrality with measured values of 162, 162, 160; the white card has a tested value of (220, 224, 223). Includes three color calibrated reference cards. Specifications: Package weight: 34g / 1.21oz Item size: 85 * 54mm / 3.4 * 2.2in Color: Black/White/Grey Package List: 1 * Neck Strap 3 * Balance Cards