However, since the tubes are not labeled with any other identifiers, with exception of matching date codes on every Tube, all I can say for sure is that Teonex had them labeled England on the box. They have matching construction comprised of a gray plate in each tube steel through plate rods, and get her Support rods, as well as high heat, dissipating shields between the top, Mica spacer and the halo getters in every tube.