Our battery boxes are cast out of 356 aluminum and black Fusioncoated. All battery box kits come complete with stainless steel 3/8 mounting studs, nuts and washers, the box top and bottom. Boxes are for batteries with the following dimensions:Group 24- 10 3/4"L X 6 3/4"WGroup 27- 12"L X 6 3/4"WGroup 30- 13 1/2"L X 6 3/4"W