hat
Liaison Sub (X peyi) igè Lachin ki itilize pou travèse fini nan gwosè yon moun ki pa marye kouche a yon lòt. Itilize tou pou prolonger koneksyon sove lavi yon pi chè konpozan forage.
eng
China Vigor's Crossover Sub (X-Over) is used for crossing over from the size of a single connection to the another. Also used for prolonging the connection life of a more expensive drilling component.