SME has created a combined axle block and axle slider piece that is designed to protect your bike, its swingarm and axle bolts. The Rear blocks are CNC machined out of 6061 aluminum. After machining we polished, anodize and engrave them. High strength stainless helical inserts are installed for use with our specially machined anodized aluminum bolts. Front axle - all spacers and axle nuts are CNC machined from 6061 aluminum and anodized in your choice of Gold, Silver, Red.Stainless steel rods are machined in house for a tight fit. The sliders are made from Black Delrin and CNC machined. Everything is made and assembled in a California facility using domestic materials.