The ECC82 is a low μ general purpose double triode. It had many uses across the equipment spectrum as well as audio.
See ECC82 for more details.
The Pinnacle logo, the word Foreign (non UK made) and the double Type designations.
The twin triodes each with an anode dissipation of 2.5 Watts.
The two piece anode is stitched and the side flanges add to the heat dissipation.
The thin glass tube envelope is 20 mm in diameter and the length excluding the B9A base pins, is 48 mm.
References: Data-sheet & 1040. Type ECC82 was first introduced in 1951.