Original vintage full wave rectifier EZ80 from the Tesla factory is a direct replacement for the 6V4 tubes. All of the available tubes are new old stock and tested. Unfortunately they were packed and longer time stored in the foil bags. Due to the temperature differences most of the color out of the printing was left there (at the foil). Tubes are electrically in perfect condition and also the pins are very nice and clean. If the remains of the incomplete, partial or disintegrated printing is a problem for you, you can easily remove it, to make them without printing (like in the picture no.5, we didn't interfere, we were just testing them all). Year of production: 1975.