SPD distribution valve is a new updated version where overflow / air channels have been made to minimize small air pockets remaining in the valve even after bleeding the brake system. SPD distribution valve uses M10x1 thread on all connections s well as the bleeding screw. This valve has no problem with leakage around threads as other can have. The bleed screw is also made of stainless steel for best durability and seals even if the valve is mounted outside the passenger compartment. Internal o-rings made of EPDM specially designed for brake fluid. These o-rings is not compatible with engine oil or other chemicals. SPD distribution valve has a new modern design that matches other SPD products. Installation: A distribution valve is used in conjunction with a hydraulic handbrake, so that the foot brake and hand brake cannot affect each other and accidentally lock up the wheels. One other benefit from using the SPD distribution valve is that the pressure from the foot brake not goes throu