HN1761 Features: -Etched: Tap size and recommended drill bit size are etched on each tool for easy identification.-Point Styles: Taper, plug, and bottoming styles are available.-All Hanson taps and dies are made in USA.-Ideal for auto repair and machinery where metric threads are specified.-The first number represents the diameter of the tap in millimeters, the second number is the distance between the threads in millimeters.-High Carbon Steel Machine Screw Thread Metric Plug Tap 18mm -2.50. Warranty: -Lifetime warranty does not cover abuse.