The CameraTrax OneSnapColor FlipCard design, with invisible magnetic latch, is a snap to open, close and use. The outside is laminated to protect the precision 24Color and 12% Grey cards inside. At 3.25 x 4.75 inches [82x120 mm], the OneSnapColor card easily slips into a shirt pocket or camera bag and at just 2 ounces [~60grams], you can take it everywhere. The FlipCard design gives quick access to both Grey and Color cards at the same time. IT'S EASY to improve the color of your photos in 3 simple steps: 1) white-balance your camera using the Grey side, 2) photograph the Color side and then photograph your subject and 3) use the auto-adjust features of your photo software in your computer. INSTRUCTIONS are included, in a 32-page full-color User's Guide, for Picasa (Free from Google), Photoshop Lightroom, Photoshop Elements and Photoshop CS4. The User's Guide also includes discussion of color balance theory and an additional section for advanced users.ADVANCED USERS: The colors are measured after the color printing cures and the RGB measured data is then printed directly on the card for every color-patch for more precision. Advanced users can follow the more in-depth procedures in the User's Guide (not provided with the 2x3 card product). The 24ColorCard is also compatible with Photoshop ACR and Adobe DNG Profile Editor for creating DNG profiles. NOTE: Like all quality photographic color references, the colors are not plastic-laminated (which would damage color accuracy) so do not let the colors get wet. The User's Guide is an integral part of the product so is not available as a free download. CameraTrax 24ColorCards are designed and manufactured in the US. Other card sizes include: -2x3 (2x3-in [50x76mm]). QUESTIONS: You can always email 'info' at CameraTrax.com .