Shimano Dura-Ace ST-R9150 is a left-side Dura-Ace Di2 shift/brake lever for 2×11-speed road setups. It is intended for riders using Shimano’s electronic Dura-Ace R9150 system, and it works with matching Di2 drivetrain components such as the RD-R9150 rear derailleur and FD-R9150 front derailleur. The lever is a good fit for riders building or replacing parts on a rim-brake Dura-Ace Di2 road bike, especially when they want electronic shifting with a compact hood shape and integrated brake lever. Manufacturer-listed weight is about 115 g for the left lever, which makes it a lighter option than many mechanical dual-control levers.