Shimano GRX BL-RX820 Brake Lever with BR-RX820 Hydraulic Disc Brake Caliper - Left/Front Flat Mount Caliper. Shimano GRX ST-RX820 dual control levers delivers light and responsive mechanical shifting for mixed-terrain riding and racing (Note: BR1060 and BR1061 are left non-shift variations for 1x set ups). The ergonomic shifter design improves comfort by decreasing pressure on your palms while the textured anti-slip brake lever surface increases control on bumpy terrain. The SERVO WAVE brake lever action provides greater braking power with improved control. The GRX BR-RX820 2-piston disc brake caliper brings a high level of control to gravel cycling with enhanced modulation and a quick initial braking point. Despite its smaller construction the system is exceptionally quiet and easy to maintain.