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99-06 GM Extended Cab Ultra Deep MAXX Dual 10/12 Downfire Box

 [Ultra MAXX]


99-06 GM Extended Cab Ultra Deep MAXX Dual 10/12 Downfire Box

Fits: 99-06 and 07 Classic GM Extended Cabs
3/4" MDF Construction
Approx. Empty Weight: 39 lbs
Installs under the rear seat
No modifications required
Does not affect rear seat latching
Seat will still go all the way down and latch
Fits 10" and 12" round or square subs
Cutout Size: 10"=9-1/8", 12"=11-1/8"
Mounting Depth: 8"
Volume: 1.13 cu.ft per chamber
Sealed Box, separated chambers
Finish: Carpet
Terminals: Installed
Logo Text: Optional
Subwoofers Sold Separately

Notice:  Please ensure your truck has the 99-06 style floor and trans tunnel under the back seat--as some 06 models have the newer body, ie 2007 style trans tunnel and seat setup which is much different.  We do not accept any responsibilty if your truck is an 06 model with newer body floor and seat.

Introducing the deepest box commercially available for your 99-06 and 07 classic GM extended cab pickups.  The Ultra Deep Maxx box is not only deeper than our Ultra Deep box, but has more volume and more clearance for your high powered subs.  Think of this box as our famous Ultra Deep box on steroids.  Now you can easily fit subs like JL 12w6 and Alpine type Rs in a box under the seat.  And since it's a downfire box, it stays completely under the seat and doesn't stick out and interfere with your rear passenger's leg room and the subs are hidden from view.  The best part is that it does not require a seat lift.  The seat will still close normally down to the stops and lock into place as usual.  This box uses 100% 3/4" MDF and is glued, countersunk and screwed, and caulked.  It is deep enough to fit many of todays deeper, beefier woofers, including: 12" Alpine Type R, 12" JL Audio W6, 12" Kicker CVX, And Many More. If you are serious about getting some major slam into your truck, then pick one of these bad boys up today. 


"Just installed my two CVR 12s in this Ultra Deep Maxx box.  Wow this is definitely a quality box.. I'll never get another cheapo box again..there's a reason those other boxes only cost 100$ thanks for the best sounding bass I've ever had"


Available Options:
Speaker Openings:
Carpet Color:
Logo Selection:
select logo choice. for no logo, select none

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by Matthew Miller Date Added: Wednesday 27 July, 2011
Wow! This box is amazing... I have two KICKER CXV 2 ohm subs in this box. Not CVR, CVX! hooked up to a Hifonics Colosuss... Needless to say, it sounds awesome, hits so freaking hard... It's deafening at times... Well worth the extra cash, if you want some serious bass in your truck!..

Rating: 5 of 5 Stars [5 of 5 Stars]
by Danial Birch Date Added: Saturday 05 November, 2016
This box is absolutely awesome, it is built very strong and the bass sounds very strong and hits hard in this box. I have two Skar vvx tens 1200wrms combined and they bang hard, I recommend this to anyone looking for a good box with huge bass!!!..

Rating: 5 of 5 Stars [5 of 5 Stars]
by jerry ross Date Added: Monday 12 March, 2012
This box is amazing. I'mm using memphis m3 12' subs dual 4ohm voice coils. They pound hard and sound great!..

Rating: 5 of 5 Stars [5 of 5 Stars]

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This product was added to our catalog on Tuesday 30 March, 2010.
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