These hubs offer the support the axles need when it comes to side forces. The hub takes the side forces when using the two bearings rather than the axle flange like the in the single bearing setup of the stock design. These hubs have a black oxide finish to retard any corrosion.
This kit includes the two hubs, two of the special bearings, two snap rings, two seals and instructions. 
Many people have opted to upgrade to using our sealed stock sized sealed bearings as the other set of bearings in these hubs instead of reusing the bearing in your car. If it's been a while since you've had the hubs off, you may want to replace your O-rings and paper gaskets while you're there.
If you're having issues with your seals properly sealing, you may want to look into redi-sleeves. These will replace the surface your seals ride on.