The Zacuto HVX200
With no options out there, Zacuto has designed and manufactured a repeatable focus system for the HVX200. When mounted, this gives the lens a hard stop at 3 feet and another hard stop at infinity making repeatable focus possible. Without it, every time you focus under 3 feet or move into the infinity range you will lose your focus marks. The unit has a witness mark and allows you to mark focus points on the lens when not using a follow focus. With an industry standard .8 gear, the focus ring allows you to work with most existing Follow Focus units.
More information about Zacuto Products (Link to Zacuto Website)