US Patent 7159491 Oil drain plug socket for a wrench assembly

A ratchet wrench, the ratchet wrench having a head portion defining a substantially cylindrical inner engaging surface and a plurality of ribs extending radially inward therefrom. The socket includes a first portion defining a plurality of depressions axially aligned with the longitudinal axis in an outer surface thereof, the first portion being releasably received by the substantially cylindrical inner engaging surface, and a second portion including a cylindrical outer surface and defining a hexagonal recess therein. A grip ring includes a knurled outer surface and is disposed on the second portion outer surface. A magnetic insert is received in the hexagonal recess.