- Portable and practical keychain: Quickly and accurately measure thread sizes with this compact tool. Ideal for on the go measurements, it provides fast and reliable results to make your work more efficient in the field or on site. - Premium materials: Made from premium metal to withstand frequent use and tough environments. Built for long lasting durability to cover all your measurement needs. - Clear dual unit markings: Features both metric and imperial units, clearly marked for easy and accurate dimensional identification. No complicated operations required—quick and error free measurements every time. - Convenient keychain design: Includes a keychain for easy carry. Attach to keys or belt, or store in a pocket or bag for access whenever you need it. - Simple operation: Designed for straightforward use with no extra steps, enabling quick identifications and measurements. Use scenarios: - On site field service and equipment repair where quick bolt and nut size checks save time. - In the workshop or garage during maintenance projects to verify fastener sizes without extra tools. - At a hardware store or parts counter to identify correct bolt or nut sizes for customers or inventory.