<ul> <li>Front side - 76.5mm inner diameter</li> <li>Rear side - M65x1 male thread</li> </ul> <p>This adapter allows using lenses with 76.5mm rear diameter of focusing helicoids with M65x1 thread.</p> <p>Made of high quality aluminium alloy.</p> <p>A lens is secured by three screws. Flat steel tension spring protects a lens body from damage.</p> <p><b>Known compatible lenses:</b></p> <ul> <li>Dallmeyer Pentac 8 inch F2.9 lens</li> </ul>