Tested on a Hickok 6000A
Average new = 2200 Minimum = 1430 (65% of average new value)
47 - 2100 / 2200 48- 2100 / 2150 49 - 2100 / 2000
Tubes 47 and 49 have matching manufacturer codes Gf2 B6I1 1022-711
Codes of tube 48 not visible. Does have 1022-71 portion.
Please note tube #2 is very dirty.
Other European 12 volt tubes available.