Shimano tourney tx rear freehub center lock disc brake quick release 8/9/10-speed. For disc brake mtbs, the shimano tx505-8 secures via a quick release.Features:Durable, long-lasting performance- Quality construction prevents axle bendingQuick and easy assembly: - Center lockSpecifications:- Brake type: Center lock disc brake- Rear speeds: 11/10/9/8- O.L.D. (mm): 135- Spoke hole 32H: Yes- Spoke hole 36H: Yes- External serration disc brake rotor lock ring Without: Yes- Internal serration disc brake rotor lock ring Without: Yes- Axle fixing method: Quick release- Quick release skewer length (mm) 166: Yes- Quick release skewer length (mm) 170: Yes- Flange distance (mm): 57.4- Offset (mm): 6.6- P.C.D. left / right (mm): 45/45- Flange diameter left / right (mm): 53.8- Spline type HG spline M (10/9/8-speed, MTB 11-speed): Yes- Engagement type: Pawl ratchet- Seal Hub: ContactTechnology:Center lock:- The Center lock system makes an easy rotor installation possible with spline mount and a lock ring. The lock ring mounting system reduces the total working hours by shortening the amount of time of both installation and de-installation. In addition, the secure fixing by the spline mount enhances precision and rigidity while improving braking efficiency.