This are the very first 555 timers made 51 years ago. Signetics was the company that invented this so popular IC. timer ever used. At first it wasn’t called 555 but the 52B and it is perhaps a prototype made before it got its final name “ 555”. This 52B were made the 4th week of 1973, just a few months after the first release in the middle of 1972. This 555 ( 52B ) are factory sealed in the original tube. You will get 2 chips ( 52B )