Filter Filters GMC Remove All Filters Price $100-$500 (196) $500 and above (20) Condition New (216) Brand Harmony Audio (216) Model Sierra (195) Envoy (9) Sonoma (9) Canyon (3) 1999-2006 GMC Sierra Ext Cab Truck Harmony F104 Dual 10" Rhino Coated Sub Box $255.99 01-06 GMC Sierra 1500 Crew Truck Harmony F104 Ported 10" Sub Box Enclosure $134.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony A102 Dual 10" Sub Box Enclosure $249.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony A122 Dual 12" Sub Box Enclosure $255.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R124 Dual 12"... $321.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R124 Dual 12" Sub Box & CXA400.1 $371.99 99-06 GMC Sierra Ext Cab Truck Harmony F104 Dual 10" Rhino Sub Box & CXA800.1 $515.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony F104 Dual 10" Sub Box Enclosure $239.99 99-06 GMC Sierra Ext Cab Truck Harmony A122 Dual 12" Rhino Sub Box & CXA800.1 $521.99 99-06 GMC Sierra Ext Cab Truck Harmony F124 Dual 12" Rhino Sub Box & CXA800.1 $551.99 99-06 GMC Sierra Ext Cab Truck Harmony A102 Dual 10" Rhino Sub Box & CXA800.1 $510.99 1999-2006 GMC Sierra Ext Cab Truck Harmony A122 Single 12" Sub Box Enclosure $150.99 99-06 GMC Sierra Ext Cab Truck Harmony R104 Dual 10" Rhino Sub Box & CXA400.1 $374.99 1999-2006 GMC Sierra Ext Cab Truck Harmony A102 Dual 10" Rhino Coated Sub Box $265.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony R124 Dual 12" Sub Box Enclosure $221.99 2004-2012 GMC Canyon Crew Cab Truck Harmony F104 Dual 10" Sub Box Enclosure New $244.99 99-06 GMC Sierra Ext Cab Truck Harmony R124 Dual 12" Rhino Sub Box & CXA400.1 $397.99 (1) 2007-2013 GMC Sierra Ext Cab Truck Harmony A102 Dual 10" Sub Box Enclosure New $235.99 1999-2006 GMC Sierra Ext Cab Truck Harmony A122 Dual 12" Rhino Coated Sub Box $275.99 2001-2006 GMC Sierra HD Crew Truck Harmony A122 Dual 12" Rhino Coated Sub Box... $295.99 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony F124 Dual 12" Sub Box Enclosure $264.99 Compatible with 01-06 GMC Sierra Non-HD Crew Cab Truck Harmony A102 Dual 10"... $484.99 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 R104 Dual 10" Sub Box & CXA400.1 $356.99 123456...9