Extru-Tech Inc. offers the mid-barrel valve and the energy management valve for increased control of specific mechanical energy, SME. Because it is an internal component, the mid-barrel valve can be added in any position along the length of the barrel for on-line control of SME and product density. The energy management valve located at the barrel discharge controls the final characteristics of the product by dynamically adjusting the extruder die restriction—even when the machine is in operation. Used together, the valves further maximize SME by manipulating product density. Their combined use also allows for quicker acquisition of product density, critical limit temperatures and pressures.