Wheels Manufacturing SOLO-XD XD/XDR Single Speed Conversion Kit - 18t For SRAM XD/XDR Freehub BLKDesigned to seamlessly transform your XD XDR hubs into a powerful singlespeed setup The Solo XD features a clever design that utilizes a base sleeve, which easily slides onto the XD XDR freehub body, mimicking the process of installing a cassette. Once the base sleeve is in place, you can effortlessly slide the spacers and cog over it, securing everything with a reliable lock ring. 7075 Aluminum carrier and cogs for durability Compatible with SRAM XD