Alloy USA ball joints have been designed with strength and dependability in mind. Construction of the ball and stud begins with SAE 4140 steel which is then oil quenched and tempered. Both the housing body and crown pressure plate have been carburized to harden the outer most layer to make it more durable while maintaining the characteristics of the base metal. Regular maintenance is quick and easy with the addition of Zerk (grease) fittings, these are not found on a standard OEM replacement.