The VI132 is a neon indicator fitted with a small bayonet cap. The later name was the CV1132.
The maker's identification. The BTH factory was located on the North West side of the mainline railway station at Rugby and were a major defence contractor.
The crown and letters AM for the UK Air Ministry.
The disc and annular electrode.
The thin glass tube envelope is 16 mm in diameter and, including the base pins, is 45 mm tall.