21FBP22A/21FGUP22 Sylvania Rebuilt C.R.T.

[walterbeers]

I believe rare earth was basically referring to the red phosphor. It was suppose to be a more vivid red as the original phosphor was more of a reddish orange look. Also the RE phosphor required less beam current to excite it, thus the red gun didn't have to run as strong as the blue and green. With the non RE phosphor tubes the red gun seemed to be the one that usually went weak first.