Completely gear driven design for slip-free and accurate movement. * Ideal for video taking with HDSLR cameras such as Canon EOS 600D, 60D, etc. * Adjustable locking system,Compatible with all DSLR cameras, video cameras, HDV, DV, specially for HDSLR camera with movie function. * Improved design, with a pair of stops on the ring for adjustable focus indication. You can control follow focus in desired range by setting the stops, and so for desired focal lengths. * Gear drive can be mounted from either side