NO GUESSWORK THREAD IDENTIFICATION - Quickly and accurately identify internal and external thread diameter and pitch.CONVENIENT THREAD IDENTIFICATION - Quickly identify threads in the shop or in the field.DUAL-SIDED THREAD GAUGES - Each size has a male and female side for quickly identifying threads on nuts, bolts, screws, hydraulic fittings, adapters, ports and more.LENGTH IDENTIFICATION - Attached ruler card measures length up to 3”.