Features of the Shimano 105 ST-R7170-L Di2 Shift/Brake Lever with BR-R7170 Hydraulic Disc Brake Caliper Wireless connection enhances the aesthetic of your bike while keeping shifting lightning fast Longer lasting - Uses two CR1632 batteries with a battery life of 3.5 to 4 years Compact, ergonomic Performance cascaded from DURA-ACE Raised hood peak improves ergonomics, while a longer hood body increases hand support Make DURA-ACE yours with custom button function and adjustable ergonomics Easily change button function with the E-TUBE app Find your optimum lever position with simple reach adjust