The United States Gypsum Co. in partnership with CEMCO, presents the construction industryA's best performing shaftwall, fire wall, and party wall components; The SHEETROCK Brand Shaft Wall System. CEMCO is the licensed manufacturer of these products, which include the CH-Stud, J-Track, H-Stud, and C-Runner components. A successful history of quality and productivity are the basis for this long-standing partnership between USG, the largest gypsum wallboard producer in the world, and CEMCO, the premier manufacturer of cold-formed steel framing products in the Western United States.