<ul> <li>Rear side - M40x0.75 male thread (match front thread of Copal No.1 shutter)</li> <li>Max. diameter - 44 mm</li> <li>Weight - 23 g</li> </ul> <p>This cap will protect your shutter when no lens installed.</p> <p>Also, you can use it as a blank to make lens adapter for Copal No.1 shutter.</p> <p>If you don't have access to a lathe, we can make you necessary female thread upon request. Possible threads are up to M35.</p> <p>Made of anodized aluminium.</p>