The ECH42 is a triode hexode mixer in an all glass envelope fitted with a B8A base and designed for radio receivers.
The second set of lettering is Telestar with a T logo above.
Little internal structure is visible, but partway up is a mica disc. This suggests that the triode is mounted above the mixer section and only a single set of copper supports can be seen at the top.
The thin glass tube envelope is 20 mm in diameter, and excluding the B8A base pins is 53 mm tall.
References: Data-sheet & 1040. Type ECH42 was first introduced in 1949. See also1949 adverts.
