Chad,
Do you know? Does the prefix "RE" in Sylvania's tube refer to Rare Earth phosphor or to REbuilt tube. I thought all 21FB & 2IFJ's contained "rare earth phosphors" (a marketing term)? Also weren't sulfide and rare earth phosphor tubes the same thing? Meaning that they had an improved red phosphor that more closly matched the blue & green phosphor in brightness value.