... Standard:ISO,ANSI,JIS,DIN,GB2.Material:Carbon steel,stainless steel,alloy steel16Mn,A299,St52-3,A387-12,13CrMo44 ... female threaded. The thread can be either straight or tapered, also referred as NPT. Generally, caps have a ... and firm friction fit while facilitating easy removal. The tapered caps are designed to provide protection for all internal ... looking forward to cooperate with you. carbon steel cap