About This ACCURATE THICKNESS GAUGE: The Performance Tool W125C is an accurate thickness gauge that can be used for a variety of applications, from measuring the thickness of small parts to checking gaps in spark plugs. DECIMAL AND METRIC SIZES: This thickness gauge comes with both decimal and metric sizes, making it a versatile tool that can be used in a variety of settings. 32 BLADES FOR PRECISE MEASUREMENTS: With 32 blades that are 3-1/2-Inches long, this thickness gauge allows for precise measurements, ensuring that you get accurate readings every time. PERFECT FOR TRANZISTORIZED IGNITIONS: The Performance Tool W125C features a .010-Inch brass blade that is perfect for transistorized ignitions, making it an essential tool for any mechanic or DIYer. SAE AND METRIC SIZES INCLUDED: This thickness gauge comes with SAE sizes ranging from .0015-Inch to .035-Inch and metric sizes ranging from .04mm to .88mm, giving you a wide range of options to choose from for any project.