Quick-Check Thread Size Keychain Tool

This thread size verification tool combines functional simplicity with mechanical reliability. Constructed from solid iron, it features precisely defined gauge notches for both imperial and metric thread systems. At just 6 cm long and 25 g in weight, it’s engineered for daily carry — easily clipped to a keyring, tool roll, or safety vest. Each slot corresponds to standard external thread dimensions, enabling instant visual and tactile confirmation. Designed for real-world use: no instructions needed, no power source required, no fragile components. Suitable for engineers, technicians, makers, and maintenance staff needing trustworthy thread ID without dependency on external references.