Feature:1. High Density: Our mountain bike hub is made of six claws with high density, which makes the ratchet teeth bite more tightly and makes the process more stable.2. Reduced Force Loss: The bike hub can bite into the ratchet after pedaling at a small angle, reducing force loss.3. Aluminum Alloy Tower Footing: The bike hub is made of aluminum alloy tower base, with a tight structure, high wear resistance and corrosion resistance.4. Built in Bearings: The bike hub has built in bearings, fluent and effortless, with a front two and back four bearing layout, easy to maintain.5. Sturdy and Wear Resistant: This bike hub is more sturdy and wear resistant, and the tower base supports for 813 speeds.Specification:Item Type: Bike Front Rear Wheel HubMaterial: Aluminum alloyOpen GearQuick Release: Front: Approx. 100mm / 3.94inRear: Approx. 137mm / 5.39inBarrel Shaft: Front: Approx. 100mm / 3.94inRear: Approx. 142mm / 5.59inBearing: 6 BearingsNumber of Holes: 32HSpeed: Tower footing support for 8-13 speeds.Package List:1 x Front Wheel Hub1 x Rear Wheel Hub4 x Accessories