The Corbin Russwin Regular Arm Parallel Bracket is the standard bracket shipped by them for the past 40 years. This replacement bracket will work on the older Corbin 100, 110, and 120's, and the Russwin 2800, 2810 and 2820's. Along with the DC3210 and DC6210 Door Closers. This bracket is required if your are going to use a parallel arm mounting, which is when you have the closer mounted on the door, on the push side of the door. Corbin Russwin part # 188F41-8.