MXW007 - 4.8mm Brass Pivot Balls Just like the brass hubs, the brass pivot balls are heavier than the standard ones, which adds more weight for better performance. While the pivot balls don't add the kind of weight to the 4x4 as the big brass hubs, it counts and will benefit proportionally from added weight, especially where its located. Comes with 12 brass pivot balls and two Allen wrenches to help with the installation.