ARP -12 Female O Ring Steel Weld Bung

ARP, short for Automotive Racing Products, was founded in 1968 in Ventura, California, USA. The company manufactures high-performance fasteners — bolts, studs, nuts, and hardware — specifically engineered for high-stress engine and drivetrain applications in racing and high-performance road use.

ARP fasteners are made from proprietary alloys including ARP2000 and L19 steel, as well as stainless and chrome-moly materials, each offering specific combinations of tensile strength, fatigue resistance, and ease of installation. Their head stud kits are among the most recognised products in the brand's range, widely used in turbocharged and high-boost engine builds where OEM head bolts are not adequate.

Beyond cylinder head hardware, ARP supplies main cap studs, rod bolts, flywheel bolts, cam gear bolts, and accessory fasteners for engines from nearly every major manufacturer. In motorsport, ARP is considered the standard for fastener reliability in built engines.