Wolftooth Center Lock Rotor Lock Ring - External Spline Securely Secures Center Lock Rotor to Center Lock Hub These are compatible with 12mm, 15mm, and 20mm thru axles and QRs. These Rotor Lock Rings are made from 7075-T6 aluminum and are machined in Wolftooth Minnesota, USA. Sold individually Compatible with 12mm, 15mm, and 20mm thru axles and QR Torque up to 40Nm Wolftooth Spack Wrench Wolftooth Center Lock Rotor Lock Ring - External Spline uses industry standard flange thickness 4mm and 44mm outer diameter, compatible with all mountain bike forks/frames and many road bike forks/frames. However, some road bike forks/frames require special thin locking rings. Wolftooth has a thin center lock rotor lock ring - internal spline. Please check your bike clearance before ordering. Tex Spec Weight: 10.5g Material: 7075-T6 Aluminum, Stainless Steel Shim Washers Made in USA