Galvanized Pressed Steel 2" (1 7/8" OD) x 1 3/8" (1 3/8" OD) Top Rail Eye Top Loop Caps sit atop line posts in a chain link fence system, allowing the top rail to slide securely through. When using a top rail for a chain link fence, one loop cap per post is required. These aluminum loop caps fit securely around the exterior of a 2" (1 7/8" OD) post and accept a 1 3/8" (1 3/8" OD) top rail.