Replace your stock oil drain plug with a neodymium magnet of 4000 gauss. Made from duralumin alloy & finished with nickeling alumite for corrosion protection. This product will collect & absorb the steel dust (iron powder) that floats inside your engine's oil. The end result is cleaner oil & removal of harmful debris. The standard Subaru engine sump/drain plug is not magnetic, but the standard gearbox & diff plugs are. However, the OEM magnetic gearbox and diff plugs are not nearly as powerful as the neodymium units in Zero/Sports Drain Plugs.