A bearing race and seal driver is a specialty tool set that installs bearing cups and rubber seals. It features a solid metal handle and a series of flat aluminum discs in various diameters. You select a disc that matches the outer diameter of the seal or the step of the bearing race. By locking the disc onto the handle and tapping it with a hammer, you drive the part into its seat. The flat surface ensures the seal goes in straight and doesn't cock sideways.
Using a socket or a block of wood is a common shortcut, but it often ruins the part. Sockets can slip and tear the rubber seal lip or chip the hardened steel of a bearing race. The driver discs are made of soft aluminum. If the tool slips, the aluminum will deform instead of scratching the steel wheel hub or housing. Drive the part in until you hear a sharp change in the hammer strike's pitch, which indicates it has bottomed out.