These boxes are so much fun! The box end twists to close and easily open again for access to all the goodies that are placed inside! The dimensions are for the actual box size and do not include the twisted ends. I thought this would be easier so you would know what you could fit in them. This box is approximately 5" x 2-3/4" x 2-3/4". All boxes are compatible with both the 8x12 and 12x12 mats, some coming with two different base boxes being machine specific. You can find additional images and a full tutorial on my blog: http://jamielanedesigns.blogspot.com/2014/09/twist-top-boxes.html