52502 Fuel Pressure Regulator. Large Seat / Carbureted (4-12 PSID). FUELAB 525 Series Fuel Pressure Regulators are designed with performance and flexibility in mind. They accept port style and non-port style union fittings without interference. The 525 Series has its return port in-line with the inlet port (not on the bottom) which allows for easy installation in extremely tight locations. Easy insallation in extremely tight locations. 6AN inlet and -6AN return port in-line. Gasoline, diesel, methanol, and ethanol fuel compatible. Billet Aluminum with anodize per military MIL-A-8625, Type II. Fine thread pitch for precise pressure adjustment. Versatile mounting bracket and stainless steel hardware. 1/8 NPT gauge port with plug for external pressure gauge. 1/8 NPT pressure reference port with barbed fitting. Most emails are answered within 24 hours, including weekends and holidays.