Genalex Gold Lion KT88 Power Vacuum Tube, Platinum Matched Quad, Pack of 4 Gold plated grid wire, carbonized screen grids, and a tri-alloy clad plate structure for exceptional performance and sound quality. "King of Power Tubes", became the heart and soul of such classics as the Dynaco Mark III, McIntosh MC275, and Marshall Major Platinum quad (4 tubes), computer-matched by manufacturer on proprietary equipment 6550 equivalent sold as pack of 4