Filter Filters Sierra Remove All Filters Price $100-$500 (185) $500 and above (19) Condition New (204) Brand Harmony Audio (204) Make GMC (204) 01-06 GMC Sierra 1500 Crew Truck Harmony R104 Ported 10" Sub Box & CXA400.1 Amp $261.99 99-06 GMC Sierra Ext Cab Truck Harmony F104 Dual 10" Rhino Sub Box & CXA800.1 $515.99 01-06 GMC Sierra 1500 Crew Truck Harmony R104 Ported 10" Sub Box Enclosure $115.99 99-06 GMC Sierra Ext Cab Truck Harmony A102 Dual 10" Rhino Sub Box & CXA800.1 $510.99 01-06 GMC Sierra 1500 Crew Truck Harmony F104 Ported 10" Sub Box & CXA400.1 Amp $274.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R104 Dual 10" Sub Box Enclosure $215.99 99-06 GMC Sierra Ext Cab Truck Harmony R104 Dual 10" Rhino Sub Box & CXA400.1 $374.99 Compatible with 2007-2013 GMC Sierra Crew Cab Truck Harmony A122 Dual 12"... $541.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony A122 Dual 12"... $491.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony A102 Dual 10"... $484.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R104 Dual 10" Sub Box & CXA400.1 $356.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony F124 Dual 12" Sub Box Enclosure $264.99 Compatible with 2007-2013 GMC Sierra Crew Cab Truck Harmony F124 Dual 12" Sub... $534.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony F104 Dual 10"... $489.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R124 Dual 12" Sub Box & CXA400.1 $371.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony F124 Dual 12"... $519.99 2007-2013 GMC Sierra Extended Cab Truck Harmony R124 Single 12 Sub Box &... $285.99 2001-2006 GMC Sierra HD Crew Truck Harmony R124 Dual 12" Rhino Coated Sub Box... $256.99 2007-2013 GMC Sierra Ext Cab Truck Harmony A122 Dual 12" Rhino Coated Sub Box... $290.99 2007-2013 GMC Sierra Crew Cab Truck Harmony R124 Dual 12" Sub Box Enclosure New $241.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R104 Dual 10"... $310.99 88-98 GMC Sierra Ext Cab Truck Harmony A122 Dual 12" Rhino Sub Box & CXA800.1 $541.99 2007-2013 GMC Sierra Extended Cab Truck Harmony A122 Single 12 Sub Box Enclosure $160.99 2007-2013 GMC Sierra Extended Cab Truck Harmony F104 Single 10 Sub Box Enclosure $154.99 123456...9