<p>This geared ring is purposed for LOMO Foton 37-140mm lens, but can be used with other lenses that have same or bit smaller focus ring diameter. Dimensions are:</p> <ul> <li>Inner diameter - 76mm; </li> <li>Outer diameter - 101mm; </li> <li>Thickness - 10mm.</li> </ul> <p>Foton lens has same diameter of the focus and zoom rings. So, you can buy two gears if you need to install them on the both rings as pictured.</p> <p>Three set screws and corresponding allen key are included into each gear delivery set.</p> <p>The lens is shown for illustrative purposes only.</p>