... many big hole, then welded many small hole, youcan change at your will.The surface is smooth, the error of opposite ... and 6mm,you can order goods.1, the widest of panel is 2.5m2, the diameter of welded is 2.5mm ... air is self-controlling4, weld the form time contracts, welds at different times5, control and reduce electrical net pollution by weaving6 ...