- Portable Precision Thread Size Check Keychain: This essential tool provides quick and accurate thread size identification within seconds, making it easy to take measurements wherever you go. - Clear Dual Unit Measurement: This keychain-sized thread checker accommodates both Metric (8 - 25 mm) and SAE (5/16 - 1") bolt sizes. Its adjustable opening allows you to seamlessly expand or reduce the measurement range, ensuring a precise fit every time. - Durable Construction: Crafted from high-quality stainless steel and aluminum alloy, this thread size checker features a polished surface for enhanced durability. Its keychain attachment keeps it accessible at all times, whether clipped to your belt or bag. - Versatile for Various Applications: Perfect for measuring nuts, bolts, and screws across different projects, this thread size finder delivers fast and reliable results. Whether you're in a professional workshop or handling DIY tasks at home, this tool is a must-have for efficiency and accuracy. - Convenience on the Go: Designed for portability, this keychain fits easily in your pocket or toolkit, ensuring that you always have a reliable measuring tool on hand for any threading challenge you encounter.