Here is a fine example of the Reflector Gun Sight, Type N-6A, as used in gun turrets of aircraft of the US Army Air Force during WWII.
From our friend Laurent at Aircraft-Gunsights.com:
"The N-6 was the first of the N- series to be specifically designed for flexible gunnery for use in turrets not equipped with compensated sights. AAF Material Command also requested the N-6 to replace the old iron sights on all other gun positions in medium and heavy bombers (but most period photos clearly show it didn’t happen).
The sight and optical system, also very similar to the ones of the N-3, were more compact. Also, it was equipped with:
- a flipping green sun filter ;
- an attachable ring and bead back-up sight in case of electrical failure of the sight;
- an easily replaceable bulb;
- a single ring with central dot orange reticle.
Early N-6s were fitted with a 29.7 mil ring reticle later replaced by a more standard 70 mil ring reticle. The N-6 was most widely used in Martin and Bendix upper turrets, B-24 turrets (nose and tail), B-17 chin turrets and on the remote control sighting station of the P-61 night fighter. Adapter rings were also available for fitment of either A-1 or A-2 tilting heads for use as a fixed gunnery gunsight on attack and light bomber plane(c), but if these combinations were ever used operationally is unclear."
This example has the manual back-up ring-and-bead sight affixed to its housing. It is in fine shape, excluding the bulb. All of the glass is intact. Measures ~7.5 inches high, and ~4 inches and 5 inches wide.