<ul> <li>Front side - M27x0.5 female thread (for Spiratone fish-eye 0.15x attachment) </li> <li>Rear side - M55x0.75 male thread</li> <li>Max. diameter - 58 mm</li> <li>Weight - 20 g</li> </ul> <p>This adapter allows using Spiratone fish-eye attachment on lenses with M55x0.75 filter thread.</p> <p>Machined of high quality aluminium alloy.</p>