Amazon.com: RED WOLF 6.5 Inch Rear Door Speaker Adapter Spacer Rings Replacement for Subaru Forester 1998-2020, Impreza 2007-2019, Legacy 2003-2014, WRX 2014-2020 2PC : Automotive
Metra Speaker Adapters for 2016-Up Subaru WRX Vehicles (Pair) Black 82-8901 - Best Buy
Leewa 2pcs 6x9 To 6.5" Car Speaker Spacer Solid For Subaru Forester Front Door Audio Pad Mat Adapter Modified Rings Kit #ca5523 - Cables, Adapters & Sockets - AliExpress
Amazon.com: Front Door Speaker Adapter Spacer Rings Fits 1993-2007 Fits Subaru Impreza - SAK026_55-1 Pair : Electronics