The ECH42 is a triode hexode mixer in an all glass envelope fitted with a B8A base and designed for radio receivers. This exhibit is branded Mullard but was made in Holland by the parent company - Philips.
See alsoUCH42 with a 100 mA heater for series heater chains.
The outer screen is sheet metal and not expanded mesh as in other ECH42s. The hole in the screen shows the triode at the top.
The hexode is mounted at right angles to the oscillator triode.
The thin glass tube envelope is 20 mm in diameter, and excluding the B8A base pins is 50 mm tall.
References: Datasheet & 1040. Type ECH42 was first introduced in 1949.