<p>This gear is purposed for Helios-44 lens, but will fit other lenses with 62mm diameter of their own focus ring.</p> <p>If your have Helios-44 lens, please measure its focus ring diameter before purchase. Different versions of this lens were made, and some of them may have different diameter.</p> <p>Installation is very simple - just slide the gear over the lens focus ring and tigth set screw gently. Set screw are installed, allen key is included into the delivery set.</p> <p>For sale is the gear only. The lens is pictured just to show how it looks with the gear installed.</p> <p> </p>