Measuring blade gauge: Made of 65 manganese steel, each measuring feeler gauge has 26 blades thickness; Foldable, easy and convenient to take and store. The space measuring tool is flexible so it is easy to get into hard to reach places. The bundle of blades are able to be kept together so you can quickly pick the gauge you need or you can unscrew the finger nut and take the feeler out that you need to use so you do not have to wield the whole set. 2 Different units of measuring: Dual marked metric and imperial, 0.0015/ 0.04 - 0.025/ 0.635 mm, the numbers of size are etched into feeler gauge for easy identification. 26 Different metric sizes (mm): .38mm, .51mm, .63mm, 76mm, 102mm, 127mm, 178mm, 203mm, 229mm, 254mm, 279mm, 330mm, 381mm, 406mm, 432mm, 450mm, 484mm, 533mm, 559mm, 584mm, 610mm, 635mm, 26 mm, Different imperial sizes (inch): 0.0015, 0.002, 0.0025, 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, 0.022, 0.023, 0.024, 0.025 inches Easy to use: The blade protector has a thumb notch to aid in removal of blades, easy to use. Wide application: They can slide in and make the measurement easily and quickly; Be applied for many different things, such as setting lifter, sparking plug, points space and so on. Specifications: Measuring range: 0.0015/ 0.04 - 0.025/ 0.635 mm Material: 65 manganese steel Blades: 26 pieces Package includes: 1 x Feeler gauge Warm notice: There is some anti-rust oil on the stainless steel feeler gauge to prevent it from rusty, please don't worry about that.