High-quality high- elastic rigid automatically adjustable 1,Connectors Material: low carbon alloy steelCraft: high pressure molding, thermal ... reducer union, core barrel reducer union, and so on.2,Connectors No.Product NameSpecifications and SizeApplication1Anchor drill rodT16*6/M14*1 ... rods9Reducer union63--73Connect drill rods10Reducer union73-89Connect drill rods3,Connectors RUILONG Coal mining ...