... 5B requirement. Range: <=10" and 8-16" two types. Taper Measuring Instruments for External Thread:This series products are high accuracy ... , reasonable design, rigid body, high accuracy indicator and sensitive movement system, conform to API Spec 5B requirement.Sizes:<=10", Indicator: 0 ... us, we will response you at the first time! Taper Measuring Instruments for API External Thread