First Color CRT Sizes (before truth in advertising)

[bhegges]

What sizes of early color picture tubes were available? This 1966 buyers guide: http://www.bretl.com/tvarticles/docu...uyersGuide.pdf references 19", 21" (round), 23" and 25" screens. I didn't think that the true 25" (25v tubes) came out until the early 1970s. Interesting though it looks like the Deceptive Advertising as to Sizes of Viewable Pictures rule came out in 1966: https://archives.federalregister.gov...343.pdf#page=2, I assume its this rule that changed the tube numbering to start with the real viewable number followed by a "V", such as 23VAXP22 for what use to be a 25XP22.

• 15 Round - 15GP22 (First color tube, briefly used)
• 19 Round - 19VP22 (briefly used)
• 21 Round - 21AXP22, 21FJP22, etc (the 21", 265 sqin, tubes as described in the buyers guide)
• 11 Rectangle - 11SP22, etc (Porta-Color & clone color sets)
• 19 Rectangle - 19EYP22, etc (the 19", 180 sqin tubes as described in the buyers guide)
• 22 Rectangle - 22EP22 (briefly used in 1957 sets, poor convergence, then withdrawn from the market)
• 23 Rectangle - 23EGP22 (First "working" rectangle color tube, assume the same size as subsequent 25 tubes)
• 25 Rectangle - 25AP22, 25GP22, etc (the 25", 295 sqin tubes as described in the buyers guide)

That leaves a question around what tube was used in the 1966 buyers guide reference to 23" 274 sqin screens? Would this have been a 25 tube but with smaller bezel or simply smaller cabinet and less generous marketing dimensions?