Thrower does not list an LF2 for Neutron only an HF2 given as a general purpose triode. The assumption we have made is that the LF2 is likewise a general purpose valve. The sketchy details for operating parameters are for the HF2.
The base is a Neutron characteristic.
The silvered dome has the identification printed onto it. The valve is British Made.
The electrodes are supported from the pinch and a glass bead. The grid wire can be seen below the bright anode. In front of the anode is the support for the top of the filament. The filament is an inverted V.
The balloon envelope is 45 mm in diameter and, excluding the B4 base pins, is 93 mm tall.
Reference: 1043. Type LF2 was first introduced in 1928.