Universal follow focus Gear rings set 6pcs from 60mm~116mm dismater for DSLR lens focusing | Size: internal diameter 60mm-116mm, external diameter 120mm; Thickness: 12mm; Net weight per piece: 40g; Material: ABS plastic; Color: black; Gear mods: standard 0.8 mod | This gear ring set are for DSLR lenses, focus ring diameter between 60mm~116mm, not lens filter size. If you cannot measure focus ring diameter, please measure focus ring perimeter, then divide π (3.1416) to get the diameter. | We also accept Customize smaller size, if your lens focus diameter is smaller than 60mm, please let us know, we will send 2pcs of rubber strips, which can be cut into pieces and pasted inside the ring | Advantage: clients can choose different size gear ring according to the lens focus ring diameter, our gear rings have unified external diameter 120mm with standard 0.8 modulus gears, photographer doesn’t need to change follow focus position for different lenses during shooting.