Distribution block connects brake lines from the master cylinder to front and rear brakes with the added benefit of a rear proportioning valve and built-in pressure activated brake light switch. The proportioning valve may be adjusted to limit rear brake pressure to help prevent rear brake lock-up. Block ports have 3/8"-24 threads that accept 3/16" inverted flare style fittings. Block includes installation instructions, fittings, pigtail wiring harness and boot.