VariZoom . VZ-SPRO-C

The Varizoom VZSPROC Pro Zoom and Focus Kit for Canon Lenses includes both the VZ-PRO-C & VZ-FCC. The VZ-Pro-C provides remote zoom control for most Canon professional video lenses and it will clamp to any tripod handle, jib, or support bar. The Pro-C features a dual-variable system for versatile, precise control of zoom speed. Set the maximum desired speed on the dial (located in a 'trigger' position), then use the pressure-sensitive rocker to vary the speed from a crawl all the way up to the preset max. Alternatively, depress the rocker fully and roll the dial with you