It is adjustable from 40-70 psi for precise fuel pressure adjustments, Has a billet aluminum construction with a black anodized base and clear anodize top for good looks, Commonly used in systems with a return line back to tank, Will work with electric pumps only, Designed for the Holley® Dominator in-line fuel pumps or other high pressure pumps where return line is needed. Holley 12-848 Dominator Billet EFI By-Pass Fuel Pressure Regulator. Holley® Billet Fuel Pressure Regulators are part of a complete line of fuel system products from Holley®. They are precision machined from 6061-T6 billet aluminum for strength and durability. They feature a black bright dip anodized body and a clear bright dip anodized top for corrosion resistance and good looks. The Holley 12-848 fuel pressure regulator features(1) -10 AN O-ring inlet, (1) -10 AN O-ring outlet, (1) -8 AN O-ring return. Adjustable from 40-70 psi for precise fuel pressure adjustments. Constructed of billet aluminum with a black anodized base and clear anodize top for good looks. Used in systems with a return line back to tank. Use with electric pumps only. (1) -10 an o-ring inlet, (1) -10 an o-ring outlet, (1) -8 an o-ring return. 1/8 NPT gauge port. Designed for use with the Holley® Dominator in-line fuel pumps or other high pressure pumps where return line is needed. By Anthony on January 05, 2020. Yes, I recommend this product. By Felix performance on June 27, 2018. Related Items / Suggested Parts. Holley 12-827 Regulator Rebuild Kit. Speedway Motors is America’s Oldest Speed Shop® and has been a trusted source for specialty rodding and racing products and friendly expert advice for more than 72 years.