This is a 3D printed set of follow focus rings for the Helios 44-2 series of lenses in a standard 0.8 degree pitch, with 97 teeth and 79mm external diameter.
It's a custom design that fits over the whole rear section of the lens and slides over the existing finger ridges for better turning, instead of just relying on friction like other designs.
A ring for the aperture is also available that also has small teeth to grip the ring, rather than just being friction fit.
Available in a range of colours.