I think it's safe since the backing plates on the longthrow polishers from Rupes is attached with a center screw and is visible when you look at the velcro on the backing plate. And they make the pads with center holes that you also see the screw through when looking at the pad attached. Then you have the spinning is so it's tightens instead of loosens I think. So with the Mille where the screws is around the center you have as rsurfer said the pad between the pad and backing plate.