This was used on the non-computing turrent guns on the B-17 , B-24 , B-25. Some scuff for years in storage. Great for the collector , aircraft museum , reenactor. Theses parts are getting harder to find after 70 plus years. The item “WW II US Army Air Force B-17, N-6A gun site” is in sale since Friday, April 21, 2017. This item is in the category “Collectibles\Militaria\WW II (1939-45)\Original Period Items\United States\Field Gear, Equipment”. The seller is “seabee1990″ and is located in Erie, Pennsylvania. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, Sweden, South Korea, Indonesia, Taiwan, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Russian federation, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Chile, Colombia, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica.