The Shimano Ultegra FD-6870-F is an electronic Di2 front derailleur designed for 11-speed road bikes with double chainrings. It mounts via braze-on, pairing exclusively with Shimano Di2 shifters like ST-6870. It handles chainring gaps up to 16T total capacity and top gears of 46-53T, covering compact and standard road cranksets. The aluminum alloy construction keeps installed weight at 138.5 g including mounting hardware, lighter than prior 6770 models by about 12 g. In real-world use, it delivers fast front shifts under load thanks to the Di2 motor, with auto-trim to minimize chain rub—ideal for spirited group rides or races where quick gear changes matter.