Cross-over sub acts for conversion and connection of drill stem component in petroleum,natural gas and geology drilling work.It is used mainly for connecting of upper drill tools and lower drill tolls during drilling operations.
Type A stand for same diameter one crossover sub has one size(D)on 0 D code A.
Type B stands for reduce type orle crossover sub has two size(D1 D2)on O D code B.
Type C is left hand tlxead type the connection thread is left hand type code C.
Lifting short sub type cross over sub has connection on one end used for lifting of drill tool(without structure drawing).