The Tektro RX 4.0 Reverse Lever works with caliper or cantilever brakes and include external cable routing. Requires mountain end brake cable.Work with caliper or cantilever brakesFits bar I.D. of 19-21mmRequires mountain end brake cableItem Specifications- LeftBrake Lever ActuationShort PullBrake Lever UseLeftCableMountainItem Specifications- RightBrake Lever ActuationShort PullBrake Lever UseRightCableMountain