Shimano dura ace r9150 di2 11sp rear derailleurcombining the very best of shimanos electronic shifting technologies with its race proven mountain bike ldquoshadowrdquo cage design, the dura ace r9150 di2 road bike rear derailleur shifts in an instant and has enhanced aerodynamics'. '.strtoupper('t')he updated cage position means it rests directly under your frames chainstay, reducing drag and protecting it in the event of an unfortunate racing incident.the shadow design also offers faster wheel changes thanks to the fact that it moves the derailleur out of the way of the dropouts'. '.strtoupper('i')t also offers faster and more precise shifting than ever before'. '.strtoupper('s')himano's 9150 groupset brings its syncro shift technology to the road too'. '.strtoupper('s')yncro shift technology enables the front derailleur to read the position of the rear derailleur'. '.strtoupper('t')he front shift is then automatically operated to position the gears in the most efficient gear and best chain line'. '.strtoupper('t')his means you'll never have to worry about front shifting and correction shifts again.features speed 11 speed compatibility shimano di2 road shifters dura ace and ultegra with e tube connection maximum low gear sprocket 30t minimum 25t minimum high gear sprocket 11t maximum 14t maximum front difference 16t total capacity 33t mount type standard hanger mount clutch type no ergonomic shifting operation without stress shimano synchronised shift low profile rear derailleur design shimano shadow cage design race endurance for less damage in a crash maintains compact and smooth appearance manufacturer's part number rd r9150 weight 204ga 2 year warranty is offered with all shimano products from chain reaction cycles 3 years on dura ace and xtr products.buy shimano components from chain reaction cycles, the world's largest online bike store.