Exterior dimensions are roughly 43 x 33 x 4 1/4 inches. You can put a duratran image in of roughly 40 x 30. Requires 4 fluorescent bulbs, not included. Unit works fine though sometimes you have to simply wave your hand over the one side of bulbs to get them to turn on. I will include 2 duratran photo art images. To change images, the black frame pulls forward and you take out some retaining clips to get the 2 pieces of plexiglass separated. Slide out one image, and put in the other. 

Use this on a wall for backlit art or for advertising for example a menu at a restaurant or whatever other purposes. 

This is a substantial item to send, so no returns, works fine, sold as-is.