Three 5TP4s Plus On The-Bay
 

FYI ... there are three (3) used 5TP4s with yokes and corrector lenses at the-Bay.
Item number: 370384242856
Not affiliated

Item #370384221367 from the same seller is an RCA optical barrel assembly.

There is also a Philips Norelco Protelgram projection assembly.
Item number: 370384186275
Not affiliated.

I'm curious -- Are these similar to the TP-4 triode CRT used in the Philco 48-2500? The appearance is similar, and the numbering scheme obviously has some similarity, although not quite the same.

The five inch RCA 5TP4 and the four inch Philco TP-400 CRTs are different.