Square plates have a crowned profile to provide maximum stud support on rubber tracks. Steel plates are through-hardened and plated with high quality steel zinc. Aluminum plates give excellent support with less weight. 7mm aluminum plates are .125 thick, 1-1/8 square and the 5/16 aluminum plates are .165 thick, 1-1/4 square. Aluminum are available in standard, powder coated colors in red, green, yellow, blue, orange and anodized purple