The Wolf Tooth MK0 Centerlock Rotor Lockring, Internal Spline version, secures a centerlock rotor to a centerlock hub with a slimmer body than Wolf Tooth's original design. Extra time in the CNC lathe narrows the profile enough to clear frames and forks that don't have room for the external spline lockring. What Our Gearhead(R) Experts Are Saying:"I count grams on every race build I put together, and this lockring cuts 27 percent off the original design's weight without losing strength where it locks onto the rotor. That's real savings for one small, inexpensive part."