These wheel cylinders contain both Ethylene Propylene (EPDM) and Styrene Butadiene (SBR) rubber components to provide superior resistance to heat, corrosion, and leakage. Meets the brake performance requirements of SAE J1153 and J1154 testing, providing reliability and quality Aazon.co: ACDelco Professional 18E573 Front Passenger Side Dru Brake... ACDelco Professional Drum Brake Wheel Cylinders use both aluminum and iron castings making them a high quality replacement for many vehicles on the road today. Pressure tested to ensure safe and confident braking ACDelco Wheel Cylinder - 18E573 - O'Reilly Auto Parts Aazon.co: ACDelco Professional 18E569 Front Passenger Side Dru Brake Cast iron and aluminum specifications; no extra stress on the brake boosting mounting RDX Groin Protector for Boxing, Kickboxing and Martial Arts, APEX Series Maya hide Super Skin Leather Abdominal Guard Cage Fighting, Abdo Gear Jockstrap for MMA , Sparring, Taekwondo, Grappling Formulated with a smooth bore finish, these cylinders have a quality seal to help increase the life of rubber components.