ROLLCii Centerlock Rotor Lockrings – External & Internal Spline are designed to securely fasten centerlock rotors onto centerlock hubs. They offer compatibility with 12mm, 15mm, and 20mm thru axles as well as QR systems. Available in multiple colors, these lockrings perfectly complement other ROLLCii anodized color accents found on headsets, hubs, rotors, and more.