The tube in the picture is not a 6AJ8/ECH81 made in Great Britain. It is really a 6JX8/ECH84 made in Spain. The tube tested bad as a 6AJ8, but I was perplexed, since it looked fine. Closer inspection revealed the type code (kd2) and factory/date code (S6D). "kd2" is the type code for ECH84, second version. For the factory and date code, "S6D", "S" is represents a Philips group factory in Barcelona, Spain, "6" is 1966 or 1976, and "D" is the month of April. A comparison picture is not given, since the ECH81 and ECH84 look identical. However, the pinouts of the two tubes are different, and the tubes are not substitutes. This was not a one-time mistake, since I was offered over 100 of these.