Speaker Install Brackets. Use for front and rear door speakers. Save time when installing aftermarket speakers. Door Speaker Adapters (double check door speaker for fitment- some might be 6x9 or other size which this won't fit with). Made specifically for most 5.25", 6" and 6.5" speakers. Usually won't work with over-sized 6.5" speakers. Speeds up installation time. Made from high grade plastic for a long lasting secure fit and corrosion resistance. Some speakers will require shaving and/or cutting these plates for them to fit right. What's included: For 4 doors: 2 pairs of speaker brackets Compatible GM Vehicles: Cadillac: 2003-2006 Escalade; Chevrolet: 2002-2006 Avalanche, 1995-2000 C/K pickup, 2005-2010 Cobalt, 1999-2006 Silverado, 1995-2006 Suburban, 1995-2006 Tahoe; GMC: 1999-2006 Sierra, 1995-2006 Yukon