Prop-block includes adjustable proportioning valve and distribution block all-in-one. Simplifies your brake plumbing. It has a black anodized finish and accepts 3/6" brake line. Adjustable proportioning valve regulates rear brake pressure, helping to maintain correct brake bias between front and rear brakes. Easy to turn handle with directional arrows makes it simple to either increase or decrease rear brake pressure. Designed for dual bowl master cylinders. Distribution block connects to the master cylinder and distributes brake fluid to all four wheels. Includes inlets from master cylinder, outlets to front brakes and outlet to rear brakes. Includes stainless steel 3/6" fittings. Includes wiring pigtail for rear brake light switch. Mount to any convenient location. This is not a direct factory replacement for original blocks and some line modifications may be necessary.