With Di2 technology shifting is easy and precise, just a light touch is sufficient for the front or rear derailleur to select the correct gear instantly.
If you haven't jumped on the electronic band wagon yet, do the research. Removal of traditional mechanical cables in favor of electrical wires eliminates poor shifting caused by contaminates, corrosion and stretching, and also provides effortless gear shifts.
Sprinter switches are used to operate the derailleurs with a tap of the thumb whilst in the drops.
Can only be used in conjunction with ST-9070 drop bar STI shifters and are supplied with 130mm E-tube electrical cables installed.