Kaavie 3 in 1 Pocket-Sized Reference Color & White Balance Grey Card Set With Quick-Release Neck Strap for Digital Photography Set of three cards, Small & Portable, Economical, Free Wrist Strap Accurate color balancing tool, works with any film or digital camera, for JPEG and RAW files Useful in pre- or post-production process Grey side 18% reflectance, white side 90% reflectance Well made and multi-purpose grey cards for any photography projects