Avid Disc Brake BB7 MTB Graphite CPS (Rotor/Bracket sold separately):

Sram:

With gobs of beautifully modulated power and intuitive easy-to-use adjustability, the BB7s set the standard in the realm of mechanical disc brakes. Inboard and outboard adjustor knobs, Tri-Align™ Caliper Positioning System™, and integrated cable stop spring tension adjustment ensures that our standard is everyone else’s goal.