The Genus Follow Focus Flexible Lens Gear Ring is a required component of any of the Genus follow focus systems, designed to mesh with 0.8mm pitch gears. Durable and highly flexible, the gear ring wraps tightly around the focus ring of any DSLR lens and can be adjusted as needed. By using such follow focus systems, it becomes much easier to achieve smooth, precise focus changes with lenses not originally designed for filmmaking.