API Spec 7-1
Drilling Lift Joint is a special tool for lifting drilling tools in oil, natural gas and geological exploration drilling operations. The hoisting pup joints with integral structure are divided into two types, A and B. Type A has a shoulder of 18 degrees, and type B has a shoulder of 90 degrees. When using, choose A or B type hoisting sub according to the structure of the elevator. All screws are standard specification for oil drill pipe.