A follow focus is a focus control mechanism used in film and video cameras. It is ergonomic rather than strictly necessary; in other words it does not contribute to the basic functionality of a camera but instead allows the operator to be more efficient and precise. It is usually operated by a focus puller but some camera operators prefer to pull their own focus. The mechanism works through a set of gears on the follow focus that are attached to teeth on the focus ring of the lens. These gears feed to a wheel which， when turned by a focus puller， will spin the teeth and thus the ring on the lens.                                    Features            Complete gear-driven design for slip-free and accurate movementAdjustable locking systemGear drive can be mounted on either sideQuick and easy installationIt offers you a fast and accurate way to focus the objectIt makes your shooting perfect and efficientUpgrade version - Screws， materials and manufacturing is much more betterCompared with the previous product， there are slightly different， the upgrade version products is more convenient and practical                                                            Specifications            Material    Completely metal. (Gear part is of brass and steel， other part is of aluminum)    <br>Rail Distance    60cm    <br>Rail Diameter    15mm    <br>Weight    974g    <br>Size    Follow Focus: (3.94 x 2.95 x 7.56) " / (10 x 7.5 x 19.2) cm (L x W x H)<br>Matching Gear Belt: (14.37 x 0.47 x 0.24) " / (36.5 x 1.2 x 0.6) cm (L x W x H)<br>Package Including: (11.42 x 7.32 x 3.62) " / (29 x 18.6 x 9.2) cm (L x W x H)    <br>Compatibility    All DSLR cameras， vedio cameras    <br>                                                            Package Includes                1 x DP500 DSLR Follow Focus for 15mm Rod Support<br>    1 x Matching gear belt (adjustable for 46mm - 110mm)<br>