"The RAP-B-200-1-386-18U consists of a interchangeable post/base pinlock system, 18"" rigid aluminum rod and single socket arm for 1"" ball bases/adapters. The interchangeable post/base system includes a diamond, round and square base, all containing the universal AMPs hole pattern. The 18"" rigid aluminum rod can be bent to position your device to its optimum viewing location. The single socket is compatible with all 1"" ball bases and adapters."