Taper measuring instruments for API external thread, Conform to API Spec 5B requirement. Range: <=10" and 8-16" two ... products are high accuracy instruments for Petro lines,mainly used to measure taper for API 5B external pipe thread, reasonable design, rigid ... body, high accuracy indicator and sensitive movement system, conform to API Spec 5B requirement.Sizes:<=10", Indicator: 0-0.5 ...