CowboyStudio 15-Inch Flexible Whip Speed Crank for DSLR Follow Focus with Standard 12mm x 12mm Square Connector One (1) Speed Crank whip for DSLR Rig Follow Focus Anti-sliding and water-proof. Large grooved knob for easy turns. Will fit on any follow focus that has a standard 12mm x 12mm square connector Makes smooth focus adjustments without adding camera shake Constructed from a solid steel spring to ensure a extended product life