A two-piece hollow design allows for the removal of any unwanted material increasing stiffness and reducing weight. Specifications: Two-piece hollow construction Fully CNC machined for precise material removal 30mm aluminium axle Compatible with almost every BB system with our extended range of BB’s 170, 172.5 and 175mm arm length available Arms available in Black, Blue, Red, Silver, Purple and Orange Self-extracting axle/arm interface Weight 518g (172.5mm and 5 bolt spider, w/o BB) It is recommended to pair this with a Hope BB. CLICK HERE FOR THE HOPE RETAINER DIRECT MOUNT CLICK HERE FOR THE HOPE RETAINER SHIMANO DIRECT MOUNT CLICK HERE FOR THE RETAINER 110 BCD CLICK HERE FOR THE RX SPIDER CLICK HERE FOR THE RX SPIDER FITTING INSTRUCTIONS CLICK HERE FOR RX CHAINLINE CHART CLICK HERE FOR RX BB COMPATIBLITY CHART