This DP500 II follow focus is improved based on the previous DP500 version I follow focus. It is consisting of a improved dampened gearbox, which promise no backlash or less backlash (<0.5mm). There is a button downside can adjust the tension of of the gearbox to reach 2 dampen level. * This improved follow focus integrated with A/B hard stops which have easy begin/end setups for fast repeatable racking between two points, and make focusing lenses that have no hard stops (such as Canon EF lenses) much easier. * Further more, the gear wheel on it can be detached and installed in other side, which makes it suitable for both left-hand and right-hand photographer. * The white mark ring is made of magnet material. It can be detached or attached very easily and quickly on metal-made follow focus. You can also buy additional mark ring.