Cassette for FPV drone fiber optic 10.2-25 km.For winding fiber optics, you can use different pipe sizes, the length of the fiber optics will depend on this.The pipes in the files are provided as a sample.For the drone, you need to purchase the pipes provided in the drawing separately; this will reduce the cost and production time. The number of kilometers depends on the length of the pipes.If you need a one-piece cassette, please consider my other product.