Phosphor bronze button 0.406 in. Lg, 0.187 shank dia. And 0.123 in. Smaller dia. Mounted on a cres plate 0.062 in. Thick by 2.000 in. Lg by 0.375 in. Wide, two slots, each 0.375 in. Lg by 0.187 in. Wide center hole 0.125 in. Diameter on which button is mounted