IMHO the comment saying ball links pop of easily is grossly in error. They are probably one of the most reliable ways to connect to a horn or servo arm. It is almost impossible for one to disconnect unless a very strong force at right angles to the normal stess is applied, even then you may have a hard time popping one off. The ball joint is supperior to clevisis, Z-bends and most other type connections, especially if you do not want any slop in the system.