, 3 mm (0.1181 in.)., 4 mm (0.1575 in.)., 5 mm (0.1969 in.)., 6 mm (0.2362 in.)., 8 mm (0.3150 in.)., 10 mm (0.3937 in.). and 12 mm (0.4724 in.). Color Coding: Removable brake disc thickness gauge uses a color-coded design to visually indicate brake lining thickness levels.