There are not multiple versions of the ET Plus® System extruder head. The design of the ET Plus® extruder head and impact plate remains the same today as when it was introduced in 2000. This fact was confirmed by an independent FHWA and AASHTO Joint Task Force, which reviewed 1,048 ET Plus® Systems in five states and concluded there’s no evidence of multiple versions. The Joint Task Force also concluded that the recently-tested ET Plus® extruder heads were representative of the devices installed across the country. The heads used in those tests were randomly selected by the FHWA from the existing inventory of the California Transportation Department.