The Di2 technology is set to be made available with electronic shifters especially for time trial and triathlon usage.
The additional units will eliminate the need to change hand position for shifting. The rider will be able to change gears at the base-bar, as well as at the bar extensions.
ST-7971 is the model number of the Dual Control Levers for time trial and triathlon. They feature a carbon lever blade that reduces the weight to 127 grams per pair. They are compatible with the new Flightdeck cycling computer with integrated buttons in the hoods.
SW-7971 is the model number of the electronic satellite switch that can be integrated easily into time trial bar extensions. The shift wires are guided through the bars for optimal aerodynamics. Weight is 103 grams per pair.
These shifters are compatible with the new DURA-ACE Di2 derailleurs FD-7970 (front derailleur) and RD-7970 (rear derailleur). They will be available in the market around three months after the availability of the regular 7970 series.