Thank you for viewing. This is a Kodak Commercial Ektar 8 1/2 inch lens. The sync contact has been modified at a reputable camera store in Tokyo, allowing for strobe photography. While I haven't performed detailed measurements like a professional, the shutter has been confirmed to function. Strobe synchronization has also been confirmed. The manufacturing year is 1950. Despite being 75 years old, the condition is good considering its age. This is a valuable vintage glass lens. No. 3 Acme Synchro Shutter, f/6.3, with a Wista Linhof board, mechanical shutter. - Model: No. 3 Acme Synchro Shutter - Aperture: f/6.3 - Brand: Kodak - Country of Manufacture: USA - Shutter Type: Mechanical Shutter