Why they would include 5mm ball heads on this unit, instead of the 4.7mm I will never know. Now you will have to buy a 5mm ball link set just be able to use this head, or figure a way how to shave them down to a 4.7mm. My 4.7mm ball link ends are VERY TIGHT on these. They are going to require I buy a reamer just to be able to make them work.