The 4-hi tower has some of the following features:-electro-mechanical web-break detector centralized oil pressure lubrication for drive gears provision for printing 4 colors on both sides of one web, or 2 colors on both sides of two webs, or single color on both sides of three webslever-type swing-down ink fountain with overrides for ink fountain roller variable-speed motorized dampeningdynamically-balanced hard chromium plated solid plate and blanket cylinderson the nose, slit or spring-type plate lock-up systemmanual sides register system for both plate cylinders, on the runrunning circumferential register on the operating sideheavy-duty timer belt drive for 4 stack unitson the run manual adjustment for registration of 4 colors on each side of web.