what is a 21gfp22 ?
 

Is this a roundie tube? A good cross for anything?

According to my 1975 RCA CRT Guide, it looks to be equivalent to the following:

21GLP22
21GNP22
21GRP22
20VAGP22*
22JP22*

*Electrically the same, but mounting hardware may have to be modified to accept the replacement type tube.

All of the above is exactly as te CRT Replacement Guide has it.

Hope it helps.

Cheers,

Oh, and it's Rectangular, Glass, Aluminized with Treated faceplate.

Cheers,

ahhh so that's what it is. Thanks.