SK (53mm flat profile / 45° with mitered corners. Double sides aluminum snap frame, width of frame molding: 53 mm (front frame all around) , the overall depth of the light box is just 48mm. The aluminium frames simply snap open and close to allow fast and easy graphic change.Edge lit with T5 fluorescent tubes EC approved or SMD led lighting. Sizes A1,A0,B0,AA and custom sizes.Can be suspended by wires from the ceiling, with fittings : two hanger,steel wire rope and aluminmum pipe for installing the light box, and power cable comes out of the top of the frame.