The Shimano Tiagra SL-4600 offers Rapidfire Plus shifting with 10-speed road drivetrain compatibility. Features: Optical gear display indicates gear position with just a glance RAPIDFIRE PLUS technology is suited to quick shifting, giving riders the ability to downshift three gears in one stroke 2WAY-RELEASE means shifts can be released by pull of the index finger or push of the thumb INSTANT RELEASE shifting releases cable as soon the lever is activated, resulting in the quickest possible gear changes SUPER SLR design makes use of a friction-reducing mechanism lever and cable that improves response and modulation OT-SP41 Specs: Rear Der/Shifter CompatibilityShimano Road Drivetrain Speeds10 ColorSilver Shifter StyleTrigger