The mechanical arm of the capping machines pick up the top, then turns 90 degrees to transfer it to the correct position, which is just under the head of the capping machines. The top is pushed up until it is held by the head, then it performs the process onto the bottle. With the unique capping machines design, it provides 100 percent perfect performance. The unique head has a pneumatic adjustable clamp. The clamp provides a 3mm allowance for error. While the holder is opened, its opening space is 3mm larger than top size. The head easily handles error allowance. The top is continually held tightly by the head clamp of the capping machines.