These are NOT good for control surfaces, especially Elevator and Aileron. They are ok for throttle, but I wouldn't even use them for the Rudder. The problem is that the little metal keeper that goes on the opposite side of the servo arm could fail or fall off. If that's the case, well, with the throttle, you can simply fly till you run out of fuel then dead-stick land.

If on a critical surface, (elevator or aileron), and it falls off, well, what are you going to do next?

Be very careful when using these things.

CGr.