This M42/AI Lens Adapter Ring for M42 Lens (Converts to Nikon AI) is a helpful adapter for Nikon AI. It brings you more convenient to take more professional pictures. This adapter ring is not only a helpful accessory for camera to protect lens and improve artistic effect as well as prolong focus and increase wide angle， but also a practical article in photography. Made ofaluminum material， this ring is solid and durable. It ensures high definition and high-fidelity pictures when taking distant objects. It s really a practical and functional helper! You deserve it!                                    Features             Simple design is easy to install and dismantle<br> Compatible with Nikon AI SLR <br> Ensure high definition from the distance<br> Made of aluminum material， it is durable in use<br> The portable design is convenient to store and use<br> It is convenient to adjust camera angle   <br>                                                            Specifications             Material     Aluminum    <br> Weight     0.74oz / 20.9g    <br> Color     Black    <br> Dimensions     (2.09 x 2.09 x 0.35)" / (5.3 x 5.3 x 0.9)cm (L x W x H)    <br> Compatible with     M42 Lens      <br>                                                             Package Includes            1 x Ring <br>