The shimano 105 r517 disc brake caliper provides disc brake power for road or cyclo cross bikes without the fuss of hydraulic fluid systems the cable operated mechanical disc brake design with independently adjustable right and left pad clearance for perfect set up means that you can upgrade to discs using existing compatible road brake levers or stis its super lightweight low profile body uses a forged one piece alloy design that increases rigidity and reduces weight and comes with resin g0