This geared ring is purposed to be installed over the original focusing ring of the Helios-44 lens (silver, 13 iris blades).

But it will fit other lenses with 60mm focus ring diameter.

Installation is simple - just put the gear over the original ring and secure three set screws with the included hex key.

If you don't need the gear anymore, removing is simple as well - loose three set screws and pull the gear off the lens.

Installation/removing takes about one minute, and doesn't require any special skills.

Dimensions:

• Inner diameter - 60 mm;
• Outer diameter - 70.4 mm;
• Thickness - 9 mm;
• Mod - 0.8 mm (pitch 32);
• Weight - 24 g.