Wilwood Check Valves or Flow Control Valves are used in conjunction with our caliper Self Bleed Lines. Together they form a closed loop brake fluid system that allows small amounts of brake fluid to circulate every time the brake pedal is depressed thereby eliminating the possibility of localized fluid boiling and build-up of gases within the brake fluid. Gases end up being vented back into the master cylinder reservoir rather than trapped within the caliper and brake lines. Our Check Valve accepts standard 1/8-27 NPT fittings. For plumbing instructions request Wilwoods Data Sheet DS-213.