1999-2006 GMC SIERRA EXTENDED CABS

• Vented box
• Fits dual 8 inch subwoofers
• Mounting depth = 7 inches
• Air Space = 1.7 cubic ft
• Tuned to 35hz
• MDF wood
• Charcoal carpet
• Available in OEM colors
• choose which side of rear seat you wish to place sub box.  Option available below.
• speaker terminal included.  Terminal shipped uninstalled due to risk of damage during shipping. It is individually wrapped and located inside the sub box.

NOTE: Boxes are carpeted in charcoal. OEM carpet colors available as option for additional cost.

NOTE: Make sure your subwoofer will work with the air space we listed. If not sure, just ask us.

Popular subs customer use for this box:

• JL Audio TW3
• JL 8W1v3
• JL 8W0
• Alpine SWRT
• Kicker CVT, CompRT, Comp, CompD and CompS
• Sundown E series

When you order this sub box, please provide us with your sub model # if you have subs already. You can type the sub model # in the comment section of the order page. This ensures we cut the holes to match your subwoofers since several subs have different hole diameters.

Hole cutouts:

• Standard hole cutout diameter for 8s = 7 inches
• If you don't know the actual hole cutout diameter, choose the standard cutout below.
• If we don't have your actual diameter listed below, choose the standard cutout, then provide us with your sub model #.  No worries, we can look up the specs of your subs.

Any questions, please contact us 850-674-6363 or sales@soundoffaudio.com

Our sub boxes are built by us! CNC precision cut and assembled by hand.

We guarantee our sub box will not fall apart.

Our competitors sell cheap pre-fab sub boxes that can't match or beat the strength and sound of our speaker boxes.

You will not be disappointed with our sub box.

NOTE:  

• Customers need to check their subwoofers' specifications to see if they will fit the sub box.  Customers may contact us if they are not sure.
• Customers are responsible for providing us with their subwoofer model # at the time of purchase, so we can ensure it will fit.  
• If customer doesn't have a subwoofer at the time of purchase, then ask us for our recommendation as to which subs will fit.  
• We can't be held liable if a customer chooses a subwoofer larger than the specs provided for our sub box.