<ul> <li>Front side - M42x1 female thread</li> <li>Rear side - M42x1 male thread</li> </ul> <p>Added optical path is 7 mm.</p> <p>This ring can be used to take macro pictures.</p> <p>The adapter consists of two parts - a body made of anodized aluminium and bronze insert.</p> <p>Such design allows positioning of your lens correctly - just loose three set screws, turn a lens together with insert to convenient position, and secure the screws again.</p> <p> </p>