Transfer connection is X-over. Transfer mode is divided into PIN * PIN (double male thread) ,PIN * BOX (one male thread and one female thread) and BOX * BOX (double female thread). Usually used to connect two ends of different calibers, different threads of products.
Specific threads are API tubing threads EUE (thickening), NUE (plain), casing threads SC, LTC , BTC , VAM series threads with high premium seal, Hydril series threads, drill pipe threads IF, REG, NPT threads, American standard threads, British standard threads and various kinds of left screw threads (reverse).
Material: J55, K55, N80, L80, C-90, C95, T95, P110, P110S, stainless steel, etc.