Metal exterior clocks are built using either steel or aluminum. The metal can be either brushed or powder coat painted almost any color. The illuminated portion of the clock is diffused with either etched acrylic blocks, a white or black thin acrylic, or is open, for a recessed cove effect. Standard sizes are 12 x 36", or 14 x 52", or one can be custom built for you, depending upon your desired metal, and size.