The Shimano GRX BL-RS717L is a left-only hydraulic brake lever option that is designed to pair perfectly with a right GRX ST-RX715 Di2 Dual Control lever thanks to its matching shape and ergonomics. Skipping all the shifting electronics, it's a lighter, simpler left brake lever option for times when less is more. The RS717 brake lever is paired with a GRX BR-RX410 flat mount disc brake caliper that brings a new level of control to gravel cycling with enhanced modulation and a quicker initial braking point. And despite its compact construction, the system is quieter and easier to maintain.