The ECF82 is a high slope triode pentode designed for television use as a frequency changer or mixer. It was also found to be effective as an audio phase splitter.
Here Mullard have added the equivalent designation of 6U8 to the envelope. The 'Made in Holland' indicates Philips production.
The bright sheet in the centre of the open anode is a beam plate. Two wire grids can be seen inside. So in fact the ECF82 is a beam tetrode.
The triode is on the right and the two grid supports on the left are the beam tetrode.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 48 mm tall.
References: Data-sheet & 1040 Type ECF82 was first introduced in 1953. See also1953 adverts.
