The Opteka Follow Focus Speed Crank for DSLR Rigs with Follow Focus features a 12x12mm universal fit, designed to be used in conjunction with follow focus systems, such as the Opteka FF180 Reversible Follow Focus, to achieve nimble and accurate focusing. It can be operated by an assistant camera operator for maximum precision and control. Fabricated from high quality, machined aircraft-grade aluminum, the Opteka Follow Focus Speed Crank for DSLR Rigs with Follow Focus is easy to attach and remove to the center of the follow focus rig with a 12mm fit and allows for quick precision and accurate focusing.