4-250A=5D22 RCA 1962 used original box sold as-is (good filament)
4-400A=8438 Eimac
4CX250B=7203 Amperex used in Eimac box as-is
4CX250B=7203 RCA open box 1971
4CX250K=8245 Eimac like new 1963 was hermetically sealed (similar to 8172)
4CX250K=8245 Eimac NOS 1960's hermetically sealed (6 in stock) (similar to 8172)
