Q-Connector Bicycle Brake Hydraulic Coupler for M9 drop bar extend tube* 3M for Shimano (ST-R9120 or equivalent)The hydraulic system became the mainstream brake system on road bikes, gravel bikes, and cargo bikes. Hydraulic brakes provide excellent power and control, but maintenance and installation can be difficult and requires specialist tools, plus the specifications of each brand are also different. Our clever Q Connector finally solves these problems for bikes with hydraulic discs. The Q Connector allows instant, tools free connecting and disconnecting of