This box can be used in one of two ways! You can use it as an open box letting the design be see-through or you can add in the secondary box to give the design color and the box a lid to close! These boxes are approximately 4-3/4" x 3" x 2-1/2" and are compatible with both the 8x12 and 12x12 mats. You can find additional images and a full tutorial on my blog: http://jamielanedesigns.blogspot.com/2014/01/one-box-two-ways.html