CLEATED BACK FRAME
Cleated back frames serve two purposes. Work mounted to thin substrates need support so that the substrate will not bend and bow which might cause adhesion problems. The frame will also float the work away from the wall providing a contemporary presentation and together with a wall cleat (shown in photo) will provide a secure method for hanging.
CLEAT AND SPACER
Cleat and spacer is a more economical way to hang work that does not require a back frame. Generally work 16x20 and smaller (with the exception of aluminum) can accomodate a cleat and spacer.