Shimano altus m310 78 speed rear derailleurthe altus m310 is an affordable but high performing rear derailleur ideally suited to a 7 or 8 speed drivetrain it has enough capacity to handle a double or triple crankset with its light action design teflon coated bushings and efficient spring this derailleur is perfect for leisure cycling and touring featurescage length long cage sgsmax sprocket 34 toothtotal capacity 43 toothspeed 78 speed weight 326ga 2 year warranty is offered with