Filter Filters $100-$500 Sierra Remove All Filters Condition New (53) Brand Harmony Audio (53) Make GMC (53) Compatible with 2001-2006 GMC Sierra 1500 Crew Truck Harmony R104 Ported 10"... $216.99 Compatible with 2007-2013 GMC Sierra Extended Cab Truck Harmony A102 Dual 10"... $390.99 Compatible with 1988-1998 GMC Sierra Extended Cab Truck Harmony A102 Single... $310.99 Compatible with 2007-2013 GMC Sierra Extended Cab Truck Harmony A102 Single... $399.99 Compatible with 2007-2013 GMC Sierra Crew Cab Truck Harmony R124 Dual 12" Sub... $336.99 2007-2013 GMC Sierra Crew Cab Truck Harmony R104 Dual 10" Sub Box & CXA400.1 Amp $353.99 2007-2013 GMC Sierra Crew Cab Truck Harmony R124 Dual 12" Sub Box & CXA400.1 Amp $386.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R124 Dual 12"... $321.99 Compatible with 2007-2013 GMC Sierra Extended Cab Truck Harmony A102 Single... $324.99 2001-2006 GMC Sierra HD Crew Truck Harmony A102 Dual 10" Sub Box & CXA800.1 Amp $479.99 Compatible with 2007-2013 GMC Sierra Crew Cab Truck Harmony A102 Dual 10" Sub... $499.99 Compatible with 2007-2013 GMC Sierra Crew Cab Truck Harmony A102 Dual 10" Sub... $424.99 Compatible with 2007-2013 GMC Sierra Crew Cab Truck Harmony R104 Dual 10" Sub... $308.99 2007-2013 GMC Sierra Extended Cab Truck Harmony R104 Single 10" Loaded Sub... $281.99 Compatible with 2001-2006 GMC Sierra HD Crew Truck Harmony R124 Dual 12" Sub... $326.99 Compatible with 1999-2006 GMC Sierra Extended Cab Truck Harmony A102 Single... $325.99 Compatible with 2007-2013 GMC Sierra Crew Cab Truck Harmony F104 Dual 10" Sub... $479.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R104 Dual 10"... $310.99 Compatible with 2007-2013 GMC Sierra Extended Cab Truck Harmony R124 Dual 12"... $312.99 Compatible with 1999-2006 GMC Sierra Extended Cab Truck Harmony R104 Single... $246.99 Compatible with 2007-2013 GMC Sierra Extended Cab Truck Harmony A122 Dual 12"... $395.99 Compatible with 1999-2006 GMC Sierra Extended Cab Truck Harmony F104 Single... $264.99 Compatible with 2007-2013 GMC Sierra Extended Cab Truck Harmony R104 Single... $236.99 Compatible with 2001-2006 GMC Sierra HD Crew Truck Harmony R104 Dual 10" Sub... $310.99 123