Shadowbox Gallery Wood Frames - Brown, 16 x 20 Wood Shadow Box Frame Interior dimensions of 16x20 inches with 3/4" of usable depth. UV resistant, framer's grade acrylic protective front. Acid Free backing board and interior walls. Hanging Hardware Included for vertical or horizontal display Interior dimensions of 16x20 inches with 3/4" of usable depth. UV resistant, framer's grade acrylic protective front. Acid Free backing board and interior walls. Hanging Hardware Included for vertical or horizontal display