TRP Spyre Post-Mount Mechanical Disc Brake, No Rotor or AdaptorsSpyre brake calipers utilize two piston movement for evenly applied rotor contact, resulting in optimum braking power and modulation. Post Mount Ramped ball bearings offer smooth pad engagement and precise modulation Brake pad composite is Resin with Metal Fibers Resin with Metal Fibers pads are compatible with Resin Only type rotors as well as standard rotors Intended for Road, Gravel and CX use Mounting hardware, rotors and adaptors sold separately