The STEELMAN 97844 8-Piece Brake Lining Thickness Gauge Set is perfect for both the professional technicians and the DIY home mechanic as an easy-to-use indicator and visual aid for determining remaining pad life. Suitable for use on both disc and drum brakes, this durable 20-gauge steel measurement tool is color coded with a durable green, yellow, or red powder coating that won't wear off to give a quick reference point on the status of your brake pads. The long measuring blade tips can fit into spaces most digital micrometers and calipers cannot to help you determine how much friction material remains on your brake pads. Each blade has its size stamped into the metal in metric as well as decimal SAE scale so you can tell with a glance a numerical value for the amount of pad you have left. The green blade tips measure .4724-inch (15/32-inch) / 12mm, .3937-inch (25/64-inch) / 10mm, and .3150-inch (5/16-inch) /8mm. The yellow tips measure .2362-inch (15/64-inch) / 6mm, .1969-inch (13/64-inch) / 5mm, and .1575-inch (5/32-inch) / 4mm. The red blade tips measure .1181-inch (1/8-inch) / 3mm and .0787-inch (5/64-inch) / 2mm.