Dura-Ace 7970 is a Di2 series from Shimano. Di2 stands for ‘Digital Integrated Intelligence’.
This innovative technology is still based on Shimano's Index System (SIS) which has proved its superiority in gear changing performance over the years compared to non-SIS systems. The difference is that the shifting is provided by electronics rather than mechanics.
Shimano's SM-EW79AI allows TT and Triathlon handlebars to be used with the 7970 system.