Fly's Magneto Cassette hub features a magnetic system engage using the force of two magnets that allows the ratchet ring to engage. The magnetic field provides an even repelling force which makes the ratchet to work completely straight and are created in a way that reduces friction compared to the use of springs. Neomidium magnets maintain the magnetic field pretty much forever, as well. These properties creates the fastest, most reliable and durable system possible. Not to mention, a pretty unique and powerful noise. The simplicity of the system is also great for customization. With only one moving part, the assembly is as easy as it can get and reduces the overall weight significantly. Fly are using heat treated CrMo caps instead of aluminum to be stiff and avoid wobble that can form over time and they are CNC machined outside and inside to achieve almost the same weight. The shell is made of a much stronger 7075 Aluminum and features the sunken spoke holes that we created with our Classic Front Hub. The driver, end caps and bolts use an anti-rust process that also gives the hub an awesome color finish. Last but not least, Fly wanted this hub to be as good as it gets, so they are having them manufactured in Europe to ensure achieve the best quality possible. Please note: this hub is not recommended for use with pegs. ###section### Product Specs HUB TYPE: Cassette AXLE: Female Bolts. Crmo version features a 14mm NDS and 14-10mm DS bolt, Alloy version features 2x 14-10mm Bolts DRIVER: 9t or 10t options DRIVE SIDE: Left Side Drive SPOKE HOLES: 36h WEIGHT: 422g (0.93lbs)