This is a NOS Philips Miniwatt ECC81 dual-triode tube. My father acquired this tube with the intention of using it in scientific equipment. This tube has an O-shaped getters and comes in an original box.

The ECC81 is equivalent to the 12AT7.

I tested the tube on an Eico 666 transconductance tester. There are no shorts and no measurable inter-electrode leakage. Merit results are 127/116%. The tube triodes are reasonably well matched, in good condition, and performing well beyond what is average for this type of tube in new condition.

The tube is marked with a group of symbols that encode the manufacturing details including tube type, factory, and date. The code on this tube is VF3 B9I1, indicating this is an ECC81 tube (VF), design code 3, made in the Mullard, Blackburn factory (B), in a year that ends in 9 (probably 1969), in September (I), week 1.