Specifications ---- Lens Follow Focus Ring is suitable lens size: 49mm, 52mm, 55mm, 58mm, 62mm ,67mm, 72mm, 77mm, 82mm. Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering. Fitment ---- Flexible Gear Belt Ring for Follow Focus can match the follow focus in a great way. And the ring belt can fit all zooming lens with size from 49mm to 82mm. Design with large external diameter, and fit most cameras and camcorders. Suitable for most shooting situations. Note ---- The focus ring is a rotatable ring on the camera body that is connected to the focus gear inside the camera lens and adjusts the focus position of the lens by rotating the focus ring to achieve a clear autofocus image. High quality material ---- High quality Aluminum alloy grip ,durable. Built-in Stainless steel screw, in accord with the global standard size. The meticulous manufacturing process and structural design ensure its robustness and strong stability. Hold better ---- They fully clamp Down you need to make sure you pull the ring as tight as you can to grip it barrel on the lens then hold your thumb on it and screw down the lever then wiggle it a bit to align it perfectly, this will work better on video lenses as they have bigger focus rings and tend to have a more grippy focus ring even with gears sometimes, I found this to hold better on my vintage lens and works like a charm.