This ball head is very professional at first, but it stops there. Clamping knobs - including that of the vice - are far from fluids, rubber covering them is very loose, slipping during tightening and tends to come out of his throat. Furthermore, the tightening causes deviation from the initial position, already very sensitive with a focal length of 200 mm, 500 mm and harmful prohibitive as soon as one uses a 800 mm, only objectives justifying the acquisition of this kind head. Moreover, there is reason to fear that the clamping system wears prematurely and rapidly loses all effectiveness. Not advised for use on the long term, if it is against to throw after a few uses and buy a new one, no problem. The "professional" adjective is not deserved in my opinion.
