The Wilwood self bleed check valves are designed to form a closed loop brake fluid system which circulates the fluid whenever the pedal is depressed, this helps prevent localised fluid boiling in the caliper. It allows gases to vent back into the master cylinder reservoir resulting in a firmer, more consistent brake pedal.Helps prevent excessive brake fluid temperature in the caliperProved a firmer and more consistent brake pedalUniversal fitment]Corrosion resistant anodised finishThese Wilwood compact check valves or flow-control valves can be used in conjunction with Wilwood caliper self-bleed lines.Inlet / outlet port size -  1/8" NPT