Heavy-Duty Construction: Synergy’s low-profile ball joint dust boots are made from thick nitrobutile rubber (NBR) for long lasting protection. The bearing surface on the lower ball joints are CNC machined from 4140 steel. 

Knurled vs. Non-Knurled: The knurled ball joints are meant for use in worn out steering knuckles, or when replacing other knurled ball joints. When replacing factory style ball joints, the non-knurled version should be selected. 

Complete Kit: The Synergy Manufacturing HD Adjustable Ball Joint Kit includes upper and lower ball joints for both the left and right side. In addition to the ball joints, this kit has grease zerks, an adjustment wrench, and installation hardware. No additional parts are required.