The 9x12 Slip-In Easel™ gives you more panel size options when painting with the LapTop Box™, Guerrilla Box™, or Hinged Front Guerrilla Box™. It can hold a panels up to 12" high by any width. The Slip-In Easel™ can also use it to paint smaller panels by putting it in upside down, so the shelf is up on top, and inserting the rods on that side.It also elevates the panel and holds it away from the lid allowing you to paint with more gestural brush strokes.