1. Upgrade to the 2025 Portable Precision Thread Size Check Keychain for fast and accurate measurements. This compact thread checker is an essential tool for quick and precise thread measurements on the go, making your work more efficient. 2. The adjustable opening and double scale design allow you to measure both Metric (8 - 25 mm) and SAE (5/16 - 1") bolt sizes. Easily expand or reduce the measuring range with clear, easy-to-read size markings for precise results every time. 3. Crafted from durable stainless steel and aluminum alloy, this keychain gauge features a multi-layer polished surface for smooth operation. Its robust construction ensures longevity, while the attached keychain keeps it accessible whenever needed. 4. The lightweight and compact design includes a convenient buckle, making it easy to attach to your waistband or bag. This feature ensures you won't misplace it, allowing for hands-free use in emergencies or during projects. Use scenarios: - Ideal for mechanics and DIY enthusiasts needing quick measurements on-site. - Perfect for engineers who require accurate thread sizing during inspections. - A valuable addition to any toolbox for hobbyists and professionals alike, ensuring you have the right tool at your fingertips.