The Ediswan Type HTB2 Barretter has a cold resistance of 7.7Ω. No operating details have yet been found.
The etched lettering on the bulb.
The normal construction for a barretter is iron wire in a hydrogen atmosphere. Here we see the fine wire coils welded to the connections that are fixed in the pinch.
Pin two has been omitted.
In the centre of the black base is the ES Ediswan logo.
The balloon envelope is 44 mm in diameter, and excluding the B4 base pins is 99 mm tall.
