Marks 2122/3-A US3 Brass Solid Replacement Keyed Alike Pair of 15/16" Mortise cylinders Lock for Iron gate Doors, designed Replacement cylinders for iron gate door locks like Marks 21AC, 22AC, 9225AC, & 9215AC. For indoor and outdoor use. The solid replacement cylinder features a standard Cam, a 5 pin tumbler, it can be re-keyed, it can work with different cams, and it is keyed different. This Marks Mortise Cylinder will fit into just about any Mortise Lock on the market. Other sizes are available depending on the door thickness.