The C-30 Clamp is made specifically for the Wimberley Head. It is 4.1" long. The clamp attaches to the Wimberley Head with two 3/8" stainless steel fasteners. The dual fasteners prevent it from moving or twisting once installed.
The C-30 clamp comes with all hardware and tools needed to fasten it to the Wimberley Head.
Note: you can also attach the C-30 to other pieces of equipment for applications where you desire a long clamp. The clamp has three 3/8" threaded mounting holes, one of which is centrally located.