The SG2V is a directly heated vari-μ RF tetrode. The screw top cap was common in the early 1930's.
Lissen only briefly made their own valves, for most of the life of the name the valves were made for them. In the Tungsram data book from the 1930's the Lissen valves are listed in the equivalents table.
The reverse is plain zinc loaded paint.
The screw top cap connection. Typical of the early 1930's.
The balloon envelope is 45 mm in diameter and, excluding the B4 base pins, is 111 mm tall.
References: 4063, 4064& 1043. Type SG2V was first introduced in 1932. See also1932 adverts.
