The D/Focus Systems D/Gear Follow Focus Gear Ring is a universal gear ring that will let you use almost any-sized lens with your follow focus.
Four sets of legs, each of a different length, come included and serve as the means to fitting a lens on the inside of the D/Gear. The legs attach on the inside similar to how spikes do on the wheel of a bicycle. A lens positions in the center of the wheel, where the spikes meet, and is pressed tight into that center by the spikes. Then you can apply your follow focus onto the exterior of the D/Gear and pull focus.
D/Gear is compatible with any standard follow focus.