"Coverage. This specification covers steel casing@ tubing and liners in the designations and wall thicknesses applicable to the four groups listed below and shown in Tables 1.1@ 1.2 and 1.3. This specification also covers pup joints@ connectors@ couplings@ and thread protection. Supplementary requirements are specified in Appendix B. Group 1 - All casing and tubing in grades H@ J@ K@ and N listed in Tables 1.1@ 1.2 and 1.3. Group 2 - All restricted yield strength casing and tubing grades C@ Land T listed in Table 1.1 and 1.3 and other outside diameters and/or wall thicknesses of grades C-90 and T-95 as agreed upon between the purchaser and the manufacturer. Group 3 - All high strength casing and tubing in seamless grade P listed in Tables 1.1 and 1.3 and all sizes 5? and larger electric welded (EW) grade P listed in Table 1.1. Group 4 - All special service casing in grade Q that is listed in Table 1.1 or other outside diameters and/or wall thicknesses as specified on the purchase order. All requirements given herein for casing and tubing shall apply to pup joints and connectors except as otherwise specified. Connectors are defined as a tubular section used for the purpose of 1) joining or changing from one size@ weight@ or type of threaded connection to the same or another size@ weight@ or type of threaded connection@ or 2) other application. In developing an order for products made to this Specification@ the user should refer to Suggestions for Ordering API Casing/Tubing to properly define specific requirements. Within this Specification: 1) ""Shall"" is used to indicate that a provision is mandatory. 2) ""Should"" is used to indicate that a provision is not mandatory@ but recommended as good practice. 3) ""May"" is used to indicate that a provision is optional. Threading Requirements. Dimensional requirements on threads and thread gages@ stipulations on gaging practice@ gage specifications and certification@ as well as instruments and methods for inspections of threads are given in API Std 5B and are applicable to products covered by this specification. Dimensional Tables. In the dimensional tables herein@ pipe is designated by outside diameter size. The outside diameter size of external-upset pipe is the outside diameter of the body of the pipe@ not the upset portion. Metric Conversions. Metric conversions of U.S. customary units are provided in the metric version of this specification. Note use of comma instead of period for decimal point in metric values. The procedures which were used to make this conversion are shown in Appendix M."