Pilot's Reflector Gun Sight Mk.II*
overall height: 10.25 inches
overall width: 4.25 inches
overall length: 5.25 inches
The Mk.IIL is a standard Mk.II* sight modified so that the pilot can adjust the angle of reflector and hence depress/elevate the line of sight.
Not sure if this helps but this is a sketch of mine of a Mk.II*. Probably not exact to the millimetre.