Looking for gunsight info

Working on a P-40F and need gunsight pics. I’ve been looking for a while on the net but havent come up with anything yet. Help?

Thanks.

EDIT: To add thanks for the help guys!

This was an N3 gunsight. Unfortunately, I’ve only got one picture and it’s worthless for modeling.

I do have an Insight resin casting of an N3-B. I can photograph that if you’d like.

A few pics here:

http://gunsight.jp/b/english/data/sight-e-aa.htm