Deatschwerks Top Feed 850cc Injectors commonly used in: * Subaru Impreza WRX (2002-2014) * Subaru WRX STI (2007-2015, and potentially up to 2020 for some flow rates) * Subaru Legacy GT (2007-2012) * Subaru Impreza 2.5 RS (97-98 models) * Subaru STI/GT EJ25 engine (various years, particularly 2004-2006 for STI, 2004-2006 for Legacy GT) It's a top-feed injector with a Sumitomo connector. The "21S-01" in the part number indicates a specific design and fitment primarily for these Subaru applications.