The 6060 is the Brimar equivalent of the Mullard M8162 special quality version of the ECC81 VHF double triode. It is useful for RF stages, oscillators and frequency multipliers, but the construction is slightly different to the ECC81. We also have the F version of the 6060 with flying leads.
We also have the Brimar 13D9 that is reported to be an equivalent to the 6060.
This is another exhibit of the same type seen face on to the triode towers.
The triode sections seen end on. The hole in the anode reveals the cathode and grid and their relative positions.
The anode box is 2 mm deep 5 mm wide and 11 mm high. This is significantly smaller than the commercial ECC81.
The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins, is 47 mm long.
References: Data-sheet & 1040. Type 6060 was first introduced in 1951.