1.This system employs hydraulic pressure for activating the plate to knock out. It is totally different from the conventional mechanical structure, and can prevent the board and the dies from being heavily impacted by the press, thus minimize the breaking of pierce pin and prolong the dies service life. 2.Simple adjustment can be made for the operating pressure for knock out and holder according to the P.C. board materials and specification. 3.Holder function is provided in order to avoid cracking, flaking and burr hole piercing. 4.Quick die change system is equipped in order to minimize the dies changing time and ensure the operation safety.