Shimano's Dura-Ace Di2 Electronic Triathlon/Time Trial Components Kit takes shifting to the next level. Say goodbye to cables stretching, constant derailleur adjustment, and say hello to instant, precision shifting time and time again. With a simple, light touch of the easily accessed shift buttons on the brake/shift levers or on the bar-end pods, you get amazingly smooth, quiet gear changes front and rear. And forget about trimming the front derailleur because the Di2 does it automatically so you never have to deal with rubbing again. The shifting is powered by a rechargeable, sealed Li-ion battery with enough run-time on each charge for about 1,500 miles. Of course the crankset and brakes deliver the world-class function that Dura-Ace is renowned for. If you're ready for the cutting edge in drivetrain technology, step up to Di2 and experience the future today.