Empty Sub Boxes. - Kick Panels. Fits 88-98 GMC Sierra Ext Cab Alpine S-W12D4 Single 12 Sub Box HA-A800.1 Amp Compatible with 1988-1998 GMC Sierra Extended Cab Truck Alpine Type S S-W12D4 Single 12" Sub Box Enclosure with Harmony HA-A800.1 Amplifier & 4GA Amp Kit.
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