The Cossor Point One Det & LF is described on its black paper label as designed for rectification (signal detection of AM signals) and low frequency amplification.
The Cossor Point One range of 1927 preceded the later unified range when the name changed to 210LF.
The gettering covers all of the glass.
The basic operation parameters are on the paper label.
The balloon envelope is 39 mm in diameter and, excluding the B4 base pins, is 82 mm tall.
References: Data-sheet, 1043 & 1040. Type Point One - Det & LF was first introduced in 1927. See also1927 adverts.
