For the unexpected obstacles of gravel riding, Shimano's GRX BL-RX812 Sub Brake Lever has your back. Designed as an auxiliary brake lever, it's mounted on the upper tops and is connected to your bike's hydraulic brake system. With this option, you'll get fast braking in an upright position that is safe and more easily accessible from multiple positions. This in-line brake lever brings greater control to the rider on mixed terrain with category-leading stopping power. The hydraulic disc sub brake offers quick access riding upright on the tops of the handlebars so nothing catches you off-guard. Thanks to the easy accessibility of this lever, you'll see less fatigue on long tours and a greater range of motion on your ride.