Extruders create objects with a uniform cross-sectional profile. Material is pushed through a die, which creates a continuous length of product. Most extrusion presses are hydraulically driven, using either a direct drive oil mechanism or gear reduction box to produce proper screw rpm and increase screw torque. The kinds of dies used vary according to the application; however, each must all allow for the continuous flow of molten polymer through the die. The extruded product is then cooled and processed downstream which can include cutting, winding, or finishing operations. Extrusion equipment is classified according to the movement of the extrusion with relation to the ram, the position of the press, the type of drive, and the type of load.