Precise Color-Coded Grading: The 8-piece gauge set features three distinct color-coded ranges for clear and precise readings. Green indicates safe thickness levels (12mm/0.4724in, 10mm/0.3937in, 8mm/0.3150in), yellow warns of approaching wear (6mm/0.2362in, 5mm/0.1969in, 4mm/0.1575in), and red signals critical wear (3mm/0.1181in, 2mm/0.0787in).