Abstract: A rotatable valve member for use in controlling fluid flow in a conduit, such as a conduit used for the transmission of liquids and gas in oil servicing operations, is disclosed. The plug valve has a rotatable cylindrical plug member received within a body member. Two semi-cylindrical inserts are positioned between the rotatable plug and the body member, each insert having a tapered outer surface and a cylindrical inner bore. A close fitting surface on the inner bore of the insert establishes a gas tight metal-to-metal seal with the plug. Lubrication is injected through the plug into a groove on the close fitting insert sealing surface. A trapezoidal seal is received in a mating groove on the tapered exterior of the insert.