focus gear size for samyang 24mm

[ReelFilmGeek]

Might be ordering the samyang 24mm photo lens because it's on sale at bh (labled as the bower brand name) and I can't justify the cine version costing $250 I'm going to need a focus gear for it. So does anyone know what size focus gear I need?

 

[legrevedotcom]

Tilta's zip gears are actually pretty nice... they are tool-less but sticks in place because of the design. Can accommodate a lot of different sizes.