What IS this??
I saw on my local CL that there is some test equipment for sale, and there was a picture of this.

It is a black and white CRT substitution kit.

Use it for testing a chassis without the need for the original CRT, or simply to test a set with a known bad CRT to see if it is worth fixing.

It probably has a 5 inch round CRT inside, although some were 8 inch.

That one looks like the 8XP4 or 8YP4. Probably the 8XP4. All the 5AXP4 ones I've seen have the round mask.

I have one ust like that and use it all the time!

This article has info about the 8XP4 testing tube and what it's good for:

http://antiqueradio.org/8XP4PictureTube.htm

This article about the 5AXP4 shows a typical kit with carrying box and cables:

http://antiqueradio.org/5AXP4PictureTube.htm

Handy things to have if you do a lot of work on vintage TVs.

Don't pay too much. They pop on eBay regularly and may sell as low as $20 or $30, although your mileage may vary.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

And remember, fellow eBay-ers, Craigslist DISCOURAGES out-of-area transactions.