The TS4 is a general purpose triode that was introduced in 1926.
The envelope is fully silvered inside.
Looking through the gettering the grid can be seen to be formed from a plate punched to leave a series of strips between end pieces. The plate is then bent into a cylinder.
The balloon envelope is 44 mm in diameter, and excluding the B4 base pins is 90 mm tall.
Reference: 1043. Type TS4 was first introduced in 1926. See also1926 adverts.
