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MB Quart FKB108

140W Peak (70W RMS) 3.5" Formula Series 2-Way 4-ohm Coaxial Car Speakers

MB Quart
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• 70 watts Peak Each, 35 watts RMS Each
• 1" Aluminum Dome tweeters
• Lightweight Thermoformed Polypropylene cone material
• Impedance: 4 ohm
• Sensitivity: 88 dB

Learn more about the fkb108

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Description


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Authorized dealer


MB Quart FKB108

The MB Quart FKB108 is a 3-1/2" Formula Series 2-way coaxial car speaker built for clear, reliable sound in compact spaces. Each speaker handles up to 35 watts RMS (70 watts peak per pair) and features a lightweight thermoformed polypropylene cone, 1" aluminum dome tweeter, and ferrite magnet structure. Its robust design includes a butyl rubber surround, natural fiber spider reinforced with epoxy, and heavy-gauge steel frame, while an integrated 6dB crossover and over-coil cooling system enhance performance. With a 4-ohm impedance, 80–20,000 Hz frequency response, and 88 dB sensitivity, it delivers high-quality audio for smaller vehicle applications.


Product Details:

  • 3-1/2" Formula Series 2-way Coaxial Car Speakers
  • Power Handling:
    • Peak: 140 watts per pair / 70 watts each
    • RMS: 70 watts per pair / 35 watts each
  • Lightweight Thermoformed Polypropylene cone material
  • Butyl Rubber speaker surround
  • 1" Aluminum Dome tweeters
  • Pure copper voice coil on Kapton former
  • Ferrite magnet motor structure
  • Textured ABS gasket assures a rigid linear seal to the mounting surface
  • Natural fiber spider for flexibility with infused epoxy for strength
  • Over-coil cooling system allows air exchange
  • 6dB internal crossover integrated into the design
  • Heavy gauge progressive-die stamped steel frames
  • Tinsel lead for high power applications
  • Use spade connectors or solder direct for best connections
  • Top-mount Depth: 1.5"
  • Cutout Dimensions: 3.41"
  • Impedance: 4 ohm
  • Frequency Response: 80 - 20000 Hz
  • Sensitivity: 88 dB
  • Authorized Internet Dealer
  • MFR #: FKB108
  • 1-year Manufacturer's Warranty

  • Priced Per Pair


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Specifications & Details


Speaker Specifications
Series
Formula Series
Priced Per
Pair
Number of Speakers
2
Speaker Size
3-1/2"
Design
2-way Coaxial
Tweeter Design
Dome
Tweeter Size
1"
Tweeter Composition
Aluminum
Woofer Composition
Thermoformed Polypropylene
Woofer Surround
Butyl Rubber
Peak Power Handling
70 watts
RMS Power Handling
35 watts
Total PEAK Per Pair/Set
140 watts
Total RMS Per Pair/Set
70 watts
Sensitivity
88 dB
Frequency Response
80 - 20000 Hz
Impedance (Per Voice Coil)
4 ohm
Shallow Mount Installation
No
Magnet Type
Ferrite
Top-Mount Depth (Mounting Depth)
1.5"
Cutout Dimensions
3.41"
CTA-2031 Compliant
No
General specifications
Marine Certified
No
Hi-Res Certified
No
Color
Black
Illumination
None
Speaker Grilles
No
Includes Damping Kit
without Damping Kit
Compatible vehicle types
Car/Truck/SUV/Van
What is in the box?
Paperwork
User manual
WITB: Speakers
Speakers (2)
Mounting screws (8)
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Manufacturer

Item Details


Manufacturer:

Model Number:

FKB108

Weight:

5.00lbs

Internal SKU:

fkb108

Internal Product ID:

146207

Customer Ratings & Reviews


MB Quart FKB108 thumbnail image

5 star
50%
4 star
25%
3 star
25%
2 star
0%
1 star
0%



Durability
4.5
Value
5
Features
4.8
Design
4.8
Usability
5

Customer Photos & Videos


Customer Reviews

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Great Sound, Poor Fit!

These speakers pack a punch for the size and price. Buyers beware, if you are installing these in a Toyota Camry, you are destined to get the red ass! The description says they would fit but I had to seriously modify the hole in the dash to even get the magnet in. It took a lot of beating to make the hole big enough and even still was a very tight fit. I was only able to get one screw in each speaker because the factory screw holes did not line up. It is such a tight space to work in, drilling new screw holes is virtually impossible unless you have a right angle drill with a very short chuck and bit. Good luck getting these installed.

By Brett on August 17, 2020

28 found this helpful


Surprisingly Great Sound

Have MB Quart 6x9s in my Jeep, so I thought I would try these in my truck. Put these in my 2011 Dodge Ram dash, and they fit like a charm with the Metra wire adapter. Nice and crisp sounding, but not too bright. Good little midbass also...that was a surprise. Compliments nicely my upgrade of door speakers (front and rear) as well as 2 - 8" subs I have under the rear seat with a small amp. All powered by the stock head unit. Plenty of loud sounds. MB Quart doesn't always get the recognition it deserves. Highly recommend.

By ensoniqman on May 16, 2020

28 found this helpful


Great Sounding Replacement Speakers

Great 2 way speaker replacement for our Jeep Wrangler JL in the dash and the (tweeter soundbar area) and price, really solid build (better than the 4" NVX I ordered for the soundbar). Easy to install, the connectors really worked out well with the blades on these speakers. They fit really snug in the dash especially with the bigger magnet and basket than the stock speakers. They sound amazing once you get the EQ set and these things dont distort (so far) and they dont get to "bright" they are being powered by the stock head unit and is enough power to clearly hear every note while going down the highway with the top and doors off. They sound really well with the Stock Alpine sub too. I do wish they would give you a gasket for when you install the speakers, so you will need that and a connector and then you're jamming out clear and loud!

By John on August 14, 2025 Checkmark Icon Verified purchase
2021 Jeep Wrangler Unlimited

5 found this helpful


These 3.5 Dash Speakers are Good!

Straight drop in for my 2026 Ram 1500, I would recommend this product

By Marketris J on May 8, 2026 Checkmark Icon Verified purchase
2019 Ford F-150
2026 Ram 1500

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