The 12AY7EH is a double triode designed for low level audio amplifier stages the equivalent 6072A is also marked on the glass. The latter is described as being for industrial and military applications that are critical as to microphonics and where reliability is paramount, ie a special quality valve.
The stage gain of 44 is around half of that obtainable with the 12AX7 type of double triode. This lower gain is deliberate so as to offer an alternative to the 12AX7.
The two box anodes. The mica sheets are not doubled as would normally be the case in SQ valves.
The working face of one triode. The anode halves are spot welded to the supports.
The thin glass tube envelope is 22 mm in diameter, and excluding the B9A base pins is 47 mm tall.