Made in USA. This GM LS Fuel Injection Fuel Filter/Regulator Kit For -6AN includes the required -6AN adapter fittings and a WIX 33737 fuel filter/regulator. Mount this filter/regulator toward the rear of your car dramatically reduces the length of your return line plumbing. Unused fuel is returned to your tank while filtered and regulated (58 PSI) fuel is passed on to your fuel rails. Injection pump is required with this filter/regulator (not for carburetor applications). We generally recommend this filter for use with pumps rated at 255 liters per hour or less (600 or less horsepower).