<p>This geared ring is purposed to be installed over original focusing ring of LOMO lenses with OCT-19 mount in Konvas housing.</p> <p>Most of such lenses have 98mm diameter of the focus ring - please check your lens to make sure before purchase.</p> <p>Installation is very simple - just put the gear over original ring and secure three set screws by means of included hex key.</p> <p>The gear has a stop rim that automatically aligns.</p> <p>If you don't need the gear anymore, removing is very simple as well - loose three set screw and pull the gear off the lens.</p> <p>Installation/removing takes about one minute, and doesn't require any special skills.</p> <p>Dimensions:</p> <p>Inner diameter - 98 mm;</p> <p>Outer diameter -110 mm;</p> <p>Thickness - 8 mm;</p> <p>Mod - 0.8 mm (pitch 32);</p> <p>Weight - 40 g.</p>