2007-2013 GMC Sierra / Chevy Silverado Ext Cab Dual 12" Sub Box + 2× Harmony HA-A122 Subs, Kicker CX600.1 Amp & HA-AK8 Kit

Package contents: one custom-fit dual 12" sealed subwoofer enclosure for 2007-2013 Chevy Silverado / GMC Sierra extended cab (down-firing, installs under rear seat), two Harmony Audio HA-A122 12" Alloy subwoofers, one Kicker CX600.1 Class D subwoofer amplifier (1200W max), and one Harmony Audio HA-AK8 8-gauge 900 Watt amp installation kit (nickel finish). Custom Chevy Silverado / GMC Sierra 07-13 Extended Cab Dual 12" Subwoofer Box - Configuration: dual 12" sealed enclosure designed for extended cab trucks (down-firing, fits under rear seat) - Mounting depth: 6" - Internal air space: 0.60 cubic feet per sub - Construction: high-quality MDF - External dimensions: Width 55-3/4" x Front Height 8-3/4" x Rear Height 5" x Depth 14-3/4" Harmony Audio HA-A122 Alloy 12" Subwoofer (each) - Series: Alloy - Power handling: Peak 1000 watts, RMS 500 watts - Sensitivity: 87 dB - Frequency response: 25 Hz - 500 Hz - Mounting depth: 6" - Mounting cutout diameter: 11 1/8" Kicker CX600.1 Car Audio Class D Subwoofer Amplifier - Class: D, Max power output: 1200 watts x 1 channel - RMS power rating: 4 ohms: 300 watts x 1 channel; 2 ohms: 600 watts x 1 channel - Variable bass boost: 0 to +12 dB at 40 Hz - Input sensitivity: Low level 125 mV - 5 V; High level 250 mV - 10 V - Frequency response: 25 - 200 Hz - Dimensions: 7-3/16" W x 8-1/8" D x 2-3/8" H Installation kit - Harmony Audio HA-AK8 Car 8 Gauge 900 Watt Amp Kit — Nickel Finish This package provides a complete subwoofer solution tailored for 2007-2013 GMC Sierra and Chevy Silverado extended cab trucks: custom enclosure sized for under-seat mounting, two high-power 12" subs, a Class D mono sub amp with variable bass boost and full-range controls, plus a heavy-duty 8-gauge nickel-finish wiring kit for installation.