Gold plated steel, mounts to chassis with four screws. Measures 1.449" X 1.119". Easy to mount on any gently curved surface such as the edge of an LP styled guitar. Mounting screws included! If you're using a USA Switchcraft jack you can thread it through the mounting hole and fasten it down with the appropriate USA hex nut. I also recommend using a lock washer under the jack and a beauty washer just under the hex nut.