Abstract: A shell featuring a main body formed of a hard and flexible sheet-like substance, such as stainless steel, is substituted for the rubber blanket of a blanket cylinder in a lithograph offset press. Perforating material that includes spaced teeth with flat edges are mounted on the impression cylinder and engage the main body of the shell to form perforations without shoulder defects. Slitting or scoring may also be accomplished by the arrangement. Stabilizing strips are positioned upon the main body of the shell in sheet-fed press applications. Flexible rubber sheets are mounted to the ends of the main body. Blanket bars are also mounted to the flexible rubber sheets. The blanket bars engage the lock-up of the blanket cylinder to secure the shell in position.