This is one of the most common industrial hollow glass production process. The glass gob is dropped into the mould, into which the extrusion punch is inserted from below. When the gob is in the preform, the mould is closed from above with the bottom of the preform, the mould is closed from above with bottom of the preform. The extrusion punch then moves upwards, forming the parison (preformed part) and the mouth. The punch is then pulled out of the parison and transferred to the finished form. Unlike the blow and blow process, the mouth is produced last during the production of wide mouth jars.