Toshiba 400KB22 Colour tube data

[BRC2000]

Hi
I have a Toshiba 400KB22 tube which tests very good the neck looks like a 21FJP22 but the face plate screen is about 17in rectangular.
Has anyone have data on this this tube such as the max EHT voltage as I was thinking of using it as a test tube for use with my RCA CTC11 / 16 roundies.
It was used in the Silvertone 5170 TV what was the max EHT used in that TV?
Thanks
Keith