1. 2025 Upgrade Precision Thread Size Check Keychains Our Thread size Checker keychains are designed for fast and accurate measurements. This metric thread checker is a small and practical tool for quick and accurate thread measurement in the field, making the measurement work more convenient and efficient 2. Adjustable Opening Double Scale DesignThe thread size checker keychain is a versatile tool that can measure both Metric (8 25 mm) and SAE (5/16 1') bolt sizes. With an adjustable opening, it's easy to expand or reduce the measuring range. The distinct and precise size scale is clear and easy to read 3. MaterialsMade of stainless steel and aluminum alloy, this portable bolt size finder keychain gauge tool has a multilayer polished surface. It's smooth, durable, and comes with a keychain for hanging on the belt, ensuring it's always within reach when needed 4. Buckle DesignThis thread size checker keychain is lightweight and compact, you can carry it with you in case of emergency. We designed a buckle to facilitate you to hang it on the waistband or bag, will not be easily lost, but also hands