... strictly from API specification and SY/5146 standard.1.Size:,3 1/2", 4",4 1/2", 5", 5 1/2",6 5/8"2.Products ... bar, fully heat treated, all physical properties conform to API Spec 7 latest edition.The integral HWDP can easily ... handling a long string of drill collars.3.Fewer tool-joint connection failures.4.Easy in handling and transporting to and ... using time. heavy weight drill pipe(integral,6-5/8")