The Tiagra SL-4600 offers Rapidfire Plus shifting with 10-speed road drivetrain compatibility. 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. Item Specifications: Shifter Style: Trigger, Color: Silver, Drivetrain Speeds: 10, Rear Der/Shifter Compatibility: Road,