The Dirt King battery tray is laser cut and bent from 12 GA mild steel. The Optima battery tray is designed specifically for the Optima 34/78 battery (Red Top & Yellow Top). The Interstate battery tray is designed for the MTZ-750T battery (Green Top). The Interstate battery tray interior dimensions are 6-7/8" W x 9-1/16" L x 7-1/4" T.