This is ECC81 RFT made in East Germany in 60s or 70s, as I know there are three different types. All of them have the same plate structure with three side holes and two very small slots. All getters have double support.
The disc getter version is second in a line. Nice sounding audio tube, better than every current production ECC81 / E81CC / 12AT7 tube.
Click to see all ECC81 12AT7 TUBES in stock