Shimano 2009
The Dura-Ace Di2 7970 package will include wired STI Dual Control levers, front and rear derailleurs and a battery pack; the rest will be filled in with standard 7900 componentry. Even with the additional electronic hardware, the complete Di2 group will still be approximately 113g lighter than the current 7800 groupset - but around 68g heavier than the standard 7900 mechanical group, according to Shimano...
http://www.cyclingnews.com/tech.php?id= ... _di2_aug08