本衬垫适用于入孔,出孔的焊接使用.This welding backing is specially designed for hand holes and manholes welding.由于有个可以呼吸通常的出孔, 我的眼睛不会起雾.With the breathing out vent, they don't fog up my eyeglasses.子弹在他的左肺上面穿出孔来.The bullet perforate...