HANGABLE FREE-FORM CLEARBACKTM
Hangable ClearBack Free-Form Shapes are crystal clear acrylic backers for glass-on-glass projects, but the backers are more durable than glass. They are drilled for a hanging system which is available or you can make your own. Each is 12 inches on the long dimension and there are 11 shapes to choose from.
see this short video on ClearBackTM