DEEP Sub box- 2007-2013 Chevy Silverado/GM Sierra Crew Dual Box - Sound Off Audio, Inc.
Amazon.com: American Sound Connection Compatible with Chevy Silverado or GMC Sierra Full Size Extended Cab Truck 1999-2006 Dual 10" Subwoofer Sub Box Speaker Enclosure : Electronics
Chevy Silverado Crew Cab Sub Box GMC Sierra Crew Cab Sub Box Sub