Mishimoto One-Way Check Valve 3/4in Aluminum Fitting - BlackAdd an extra layer of protection to your catch can set up with the Mishimoto Performance One Way Check Valve. The 3 4 inch diameter valve has a maximum pressure rating of 100psi and allows for ample airflow through the system, while protecting vital components from unwanted pressure The anodized aluminum housing ensures durability of the check valve, and the Viton diaphragm and seals provide superior chemical resistance. Our Check valves are not only