This is an OEM Subaru brake pedal switch kit. The original brake pedal switch on this car used a housing with plastic threading, but we are told that these developed problems with moisture, so what you get now as a replacement is an older-style switch with metal threading, plus an adapter harness and a washer and nut to retrofit the other style switch.
Fits all 2008-2014 Subaru WRX sedan. Note that the HATCH version of those cars uses a different switch.