The Aeroflow brake combination proportioning valve simplifies the brake proportioning adjustments on vehicles with custom brake systems. It allows a more accessible mounting position next to the brake master cylinder using the bracket (AF300-149 Sold Separately) and less hardline plumbing. This combination block maintains complete isolation between the front and rear fluid circuits in the tandem master cylinders. The rear circuit has a single inlet and outlet with an adjustable proportioning valve. The front circuit has a single inlet with two outlets. It can be run as a single outlet with one outlet plugged in or used to split the plumbing on its way to the front brake calipers. Each inlet and outlet port accepts 3/16” brake lines with 3/8”-24 inverted flare females. A remarkable feature of this unit is the built-in brake light switch. This brake light switch lets you activate your tail lights with hydraulic pressure from your brake system.