The Lisle Corporation Truck Brake Lining Gauge Set, No. 83400, is designed to measure truck disc brake pad wear accurately and consistently. The 9-pc manual brake gauge set checks both straight on or at a 90 degree angle to the rotor with offset tips. Brake lining gauges identify thickness levels for brake lining inspection. The set is made from durable, flexible acetal. It includes 22mm (.8661"), 20mm (.7874"), 18mm (.7087"), 16mm (.6299"), 14mm (.5512"), 12mm (.4724"), 10mm (.3937"), 8mm (.3150"), and 6mm (.2362").