The Imperial Box #0 is a cast-aluminum mailbox with smooth sides and door. It includes one large brass knob, a small hinge, a flag assembly and any necessary hardware. BOX 0 Height: 8.5″ x 11″ x 20.5″ BOX 0 Weight: 12.10 lbs. NOTE: This is a Standard sized box, and it uses a hinge with three holes. If your current box has four holes in the hinge, you have an Estate sized box. Shop for Estate Boxes here: Estate Sized Boxes. There are 2 holes on the top of the mailbox for a number plate. There are 4 holes in the back of the box to mount to the post. There are 2 holes in the top left of the box on the right side of box that are used for the flag assembly which comes with this product.