Can be used horizontally or vertically. The outside dimension is 8 x 10" to fit a standard frame. The openings are 2 1/4" x 3 1/4" . Can be used horizontally or vertically. Colors we have in stock are in the second picture. They are from left to right: Brite White, Light Grey, Medium Grey, Soft white, Pink, Cream, Red, Kelly Green, Spring Green, Forrest Green, Silver Blue, Royal, S Fabric matting is also available. Fabric matting adds an elegant touch. We can do this multiple opening mat in any size you like with other opening sizes and outside dimension. Just let me know what you are looking for. CHOOSING THE CORRECT MAT SIZE When purchasing a mat for a picture frame be aware that your standard frame should measure at least 1/8” larger than the size of the mat you purchase. In other words an 11 x 14” frame should actually measure at least 11 1/8” x 14 1/8”. You mat will measure 11 x 14”. In addition there is a 1/16” allowance on the mat so it can measure 10 15/16” x 13 15/16” up to 11 1/16” up to 14 1/16” and still fit in your standard frame. Some less expensive frames may not have the allowance so you would need to ask for a size that is at least 1/8” smaller than the opening on the frame itself. All are mats are individually custom cut "one by one" for your order specifically. We do not stock them already cut . For that reason they cannot be returned but if you have a problem please contact us and we will see what we can do to resolve your problem.