GMCO Grade E Rotary Drilling Couplings have set the industry standard and were the first swaged-on grade E fitting to be successfully marked in the world. They are a one piece welded design and provide a permanent end connection to high pressure API grade E drilling and vibrator hoses for use in the toughest oil field applications. Constructed of coupling grade schedule XXH N/L 80 4130 and special George Myer spec A 513 DOM tubing materials to provide years of trouble free service. GMCO Grade E Swage Fittings are specially designed for use with a wide variety of manufactures’ steel wire reinforced drilling hoses and require no set screws for coupling retention.