CTA Tools A311 25-Blade Extra Long Feeler Gauge is designed for long reach applications, especially diesel. There are 25 removable blades, each 12-inch long, that have metric markings. Blade sizes are 0.0015, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, 0.020, 0.021, 0.025, 0.027, 0.030 and 0.040-inches. California Prop 65 - Warning, This product contains chemicals known to the State of California to cause cancer, birth defects or other reproductive harm.