[Amps] cheap glass vacuum tube

[Hsu]

I found a very cheap industrial vacuum tube($100 or so) ,Chinese named FU-605, same as (Toshiba?) 6T51, simlat 7072, but mu=48.
   the vacuum should be better than 833A, and more powerful power(2.5KW@ 50MHz,Va=4000V), would anyone
 had ever use it as Class AB1 RF amplifier?
     73! Hsu