Camtree Prime Follow Focus is small, packable and designed to last longer than any other follow focus you will ever own. If you need a tiny, sturdy, single-operator focus tool, then look no further. You have found it! Specifically designed for pancake lens and prime lens, this is another quality product from Camtree. What's In The Box: Prime Follow Focus, Follow Focus Whip Adapter, Gear Ring for prime lens, Gear belt, White Drive Gear. Exclusively designed for all small pancake lens and prime lens. Sturdy yet lightest single-operator focus tool. Flexible drive gear belt for no backlash. Easy operation and long life usage. Unbeatable value added price. Our Quality Assurance Guarantee. Specifications: Rod Diameter - 15mm, Made from - CNC, Drive Gear Diameter - 39mm, Length of Rotating crank - 8 cm.