The SHAPE Follow Focus Pro mounts on 15mm rods and features an adjustable arm which puts the gear at the optimal position for the lens, no matter what the diameter is. The unit snaps onto 15mm rods, allowing for quick attachment, removal, and re-positioning. Two 0.8 pitch gears come included and give you a choice of either 28 teeth or 43 teeth ? depending on the throw distance of the lens. Additional features include two adjustable hard stops, removable marking disc, and an industry standard accessory port for using optional whips and cranks.