Follow focus kit's are now more popular than ever, with the introduction of DSLR cameras and all the manual lenses that come with them. It's pure role is for ergonomics rather than practical application. It helps for both single and two person crew. Alowing better access and easier movement of the focus ring on lenses. Almost a compulsory piece of kit. The follow focus make precise and repeatable focus pulls smooth and accurate and come with wireless options.