The panel is a back plate mounting panel designed for the 5" house & letters. The back plate is available in the following sizes that accommodate a single digit or up to 4 numbers. The mounting panels are machined from a solid piece of aluminum with a 4mm solid material thickness. The numbers / letters are mounted onto the panel which have pre-drilled holes based on the exact numbers and letters that have been order. Concealed mounting studs anchor the panel to the wall. The mounting panels are available in satin black, bronze, satin alu or in brass. How do you order the plate? The panel can only be ordered in conjunction with the 5" numbers, the holes are pre-drilled for the numbers you are ordering.