from Engadget by Thomas Ricker

If the idea of wrist-twist is too taxing, perhaps an electronic shifter is the best option to get your meat-bag mobile. With the press of a button, the Shimano Di2 derailleur on this $10,000 Merida Scultura 909 road-racer automatically eases you into that next gear. Now shipping on select bicycles, the Di2 system features a rechargeable Lithium Ion battery (lasting 1,000 kilometers or 621 miles) powering an integrated CPU that monitors and adjusts the front and rear derailleurs to keep them perfectly trimmed. The system allows you to shift 30% faster (as fast as you can move your finger) than with mechanical derailleurs — even under load while cycling out of the saddle. Great for pros (we guess). For everyone else there’s Vespa.

Shimano Di2 Electric Shifters

Link to video