For measuring clearances from 0.002 to 0.025" (0.051 to0.635mm). Gauge includes 9 steel blades and a 2" steel ruler. Blades include: 0.002, 0.003, 0.004, 0.005, 0.006,0.008, 0.020, 0.022, 0.025. Metric and standard measurements on blades. Meets Fed Spec. GGG-G-17c.