Aero Vintage Books

Hello:
So way back when my grandfather bought a ball turret gunsight, and another box marked only "Caution: This sight to be used in a nose cone only."
He got them thinking that if he ever needed a specific gear ratio for a project, it was probably in there somewhere.
I'm trying to identify the second one and what it is off of.
Pictures below.
Any idea what this is off of?




I think I found what this is from, B-17 lower ball turret.

The K-4 is indeed a Sperry ball turret computing gun site.
A K-3 would be for the upper turret.

The "Sight to be used in a nose cone only" is for a K-11 gunsight, while the K-10 was for the nose turret. I believe these were used in later model B-24s and certainly in the B-32.
Nick