The high-quality WALGUN M1R BOOST front hub is made of ultra-light AL7075/AL6061 aluminum alloy CNC machined, with 4 pieces stainless steel sealed bearings, suitable for 148mm wide mountain bike BOOST frame, the brake disc of the hub is 6-bolt installation, The hubs have 28 and 32 holes. It is suitable for 8-12 speed mountain bike shimano sram cassette, It is available in 3 freehubs with HG XD MS-Micro Spline.