Green Lens Holder for an Aldis Signalling Lamp.
The front of the metal ring: part of an Aldis lamp.
The Air Ministry stamp on the front of the metal ring with the part number 5A/1320.
The reverse of the metal ring, showing the clips that would have held the lens in place.
An Airman using an Aldis Lamp at RAF Catfoss, Yorkshire, in April 1941.
F/O B. J. Daventry. RAF official photographer.