Brake Lining Thickness Gauge Set ( Commercial Truck ) Includes 9 blades of different sizes ranging between 6 ~ 22 mm ( 0.2362" ~ 0.8661" ) Identify thickness levels for brake lining inspection. Gauges match SAE or metric recommendations for brake service. Made of durable, flexible plastic. Gauge sizes are 6, 8, 10, 12, 14, 16, 18, 20 and 22 mm. 6mm ( 0.2362" ) 8mm ( 0.3150" ) 10mm ( 0.3937" ) 12mm ( 0.4724" ) 14mm ( 0.5512" ) 16mm ( 0.6299" ) 18mm ( 0.7087" ) 20mm ( 0.7874" ) 22mm ( 0.8661" )