According to Shimano:
Tactile feedback to the rider that the gear shift has been completed
Light action, define click engagement Vivid index shifting
Short lever stroke response
Powerful and controllable braking system
Carbon brake lever
New Ultegra Polymer-coated Shift Cable
The Shimano Ultegra ST-6800 Shifters are quality shifters built to give you top performance every ride. In the process of making their Ultegra line an 11 speed, Shimano also upgraded the Ultegra Shifters, giving them a new look and new technologies. One of those technologies is the redesign of the shifter body to make it more comfortable to hold while riding. Shimano also changed the pivot point to make braking with your hands on top of the hood easier. To make your shifting faster, the shift lever is angled slightly out and shaped with more material on the outside so you can find it faster. To give you more control over your shifting, the Ultegra ST-6800 Shifters allow you to upshift one sprocket at a time and downshift three sprockets at a time. Shimano has given these shifters a carbon fiber lever to make the shifter lighter and more durable. The Shimano Ultegra ST-6800 Shifters are designed to work with Shimano 11 speed double drivetrains. Includes poly coated shifter cables.