This exhibit is an ECC82 that came in an orange coloured CPC box. The valve has the Type designation etched into the glass as well as the printed pejorative term Foreign. CPC were, and are, professional electronics suppliers in the UK and they own Farnell.
Designed as audio and general purpose triodes, two independent valves exist in the envelope. The 6C4 has almost the same rating as half of an ECC82.
The normal anode box is formed of two plates stitched together.
The thin glass tube envelope is 20 mm in diameter and the length excluding the B9A base pins, is 48 mm.
References: Datasheet & 1040. Type ECC82 was first introduced in 1951.