The TO1 standard was the first all-metal case used for germanium transistors when the black glass models were abandoned around 1964. This concerns European series like ACs, industrial series ACYs, ASYs, ASZs, the british NKTs and the japanese 2SAs…In the USA, there are larger JEDEC standard cases (TO5 box) or smaller (TO18 box) as the european TO1.Transistors manufactured in Eastern Europe used an elongated version of the TO1 case : some ACs, SFTs manufactured under license, and the national productions in the East. The TO1 dimensions were not strictly followed by all manufacturers, which can seem surprising nowadays. From another...