Best thing to do is to identify a tube with similar characteristics that your tester does have setting for, and other than potentially making an allowance for heater/filament differences in voltage between the tubes to be tested, and the tube with similar characteristics, you can at least determine an approximate merit.
Relevent specs are:
Filament- 4.5 volts
Max plate current 50 ma
Max plate voltage 450
Max grid current 10 ma
Amplification factor of 7.2
Base pinout according to 1950 ARRL handbook is 4D.
If you have a listing for a "10" or "10Y", you could try those, other than the filament voltage- it is different- the other ratings are close enough to give you an approximate idea of quality. The equipment it would go into would be the final determinating test.
The 205B was limited in upper frequency range, but is fine below 6Mhz.
:please help, how do i test a western electric 205d triode? is there a special tester i should look how can i jumper up something? i have to test 6 tubes.