The M8162 is a special quality version of the ECC81. It is a VHF double triode, useful for RF stages, oscillators and frequency multipliers, but the construction is slightly different from the standard version in that double micas, or thick mica sheets, are fitted to reduce the effects of vibration.
The anode is made of pressed sheet as normal, the box is closed on all four sides. The anode box is 2 mm deep 5 mm wide and 11 mm high. This is significantly smaller than the commercial ECC81.
The twin triodes with the grids visible through the side of the anode.
The M8162 is identical to the CV4024 and the 12AT7WA as these designations are also on the glass.
The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins, is 46 mm tall.
References: Data-sheet & 1040. Type M8162 was first introduced in 1954. See also 1954 adverts.