This is the fotga DP3000 follow focus kits. * Precise design, with AB Stop, Follow Focus ,which have easy begin/end setups for fast repeatable racking between two points * Additional marker design besides AB hard stop. * The particular part of this follow focus is that it can use different size gears. It can work with 3 different size gear to meet your different needs with various lens: 38T : 38x0.8mm pitch, diameter: approx.28mm 43T: 43x0.8mm pitch, diameter: approx.31mm 65T : 65x0.8mm pitch, diameter: approx.49mm