This is a direct replacement of the stock bearing, but it is a sealed bearing. This means, gease stays in, dirt stays out. These last much longer than the stock bearing. We also HIGHLY recommend them with your double bearing hubs. The double bearing hub kit only comes with the special bearings with the idea that you will be reusing your stock bearings as the other set. If you want yet another upgrade, add these to the list. Price is per bearing.