The EV series gauges with amp boxes are considered "matched" from the factory, but this is mainly an issue with the electric temperature gauges. These are contract manufactured for us unlike all of the "modern" gauges like EV2 and Performax series which are built here. By matching the sensors and amp boxes the factory is able to use wider tolerance parts, but for replacement parts we insist on tighter tolerances which allow them to be "generic" without matching them. The pyrometer amp boxes are not matched since the sensors (thermocouples) are sold separately.
