Garage
Shop

See all parts that fit your 2010 IS250C

Polk Audio MM521 Open Box, Very Good Condition (Used)

5.25" 2-way Mobile Monitor Series Coaxial Speakers (Marine Certified) Open Box, Very Good Condition (Used)

Polk Audio
Shop all Polk Audio
highlight-star-icon

• Open Box Complete
• Peak Power: 200W
• RMS Power: 90W
• 2-way Marine Certified Coaxial Speakers
• Woven glass composite cone woofer
• Butyl rubber surround for a smoother response
• 1" Silk/Polymer composite swivel tweeter
• Klippel optimized components for distortion-free sound

Learn more about the ls-mm521-obc6

We apologize

This item has been discontinued

NVX - Worth the Envy - Direct to Consumer Car Audio

Description


Polk Audio brand icon

Authorized dealer

Item Condition - Open Box, Great:

This product works like new, is well-cared-for and in great condition. May show limited signs of wear or use and may be missing non-essential parts, accessories or original packaging.

Will fit most 6x9" and 5x7"/6x8" locations,
with appropriate speaker adapter. Click "Related Items" Tab.

MM Series Superior Performance

The Mobile Monitor Series by Polk Audio is the result of 3 years of research and development. The series uses high quality materials and the newest loudspeaker technology to bring the listener an unforgettable experience. The best part about the MM Series is the affordable price.

  • A part that is fully functional but shows no sign of use outside of installation.

General Features

  • 5-1/4" 2-way MM Series Marine Certified Coaxial Speakers
  • Power Handling:
    • Peak: 400 watts per pair / 200 watts each
    • RMS: 180 watts per pair / 90 watts each
  • Woven glass composite cone woofer
  • Butyl rubber surround for a smoother response
  • 1" Silk/Polymer composite swivel tweeter
  • Klippel optimized components for distortion-free sound
  • 2.7 ohm impedance
  • 25mm Large diameter voice coil increase reliability
  • Carbon composite basket
  • Neodymium magnet structure for more power
  • Top-mount depth: 2-1/2"
  • Authorized Internet Dealer
  • 90 Day Manufacturer's Warranty

Priced Per Pair

Important Note: Polk Audio specifies the nominal impedance of these speakers to be 2.7 ohm. The product box states the impedance to be 4 ohm and the speaker magnet shows 2 ohm, this has been confirmed by Polk Audio to be an incorrect specification. The product manual is correct in stating the nominal impedance of the MM series of speakers to be 2.7 ohm.

Specifications & Details


Speaker Specifications
Series
Polk MM Series
Priced Per
Pair
Speaker Size
5-1/4"
Design
2-way Coaxial
Tweeter Design
Dome
Tweeter Composition
Silk-Polymer Composite
Woofer Composition
Woven Glass Fiber
Woofer Surround
Butyl Rubber
Peak Power Handling
200 watts
RMS Power Handling
90 watts
Sensitivity
92 dB
Frequency Response
50 - 25000 Hz
Impedance (Per Voice Coil)
2.7
Top-Mount Depth (Mounting Depth)
2-1/2"
Cutout Dimensions
4-11/16 x 4-11/16 
General specifications
Speaker Grilles
Yes
Warranty and Return Policy
Parts Warranty Duration
90 days
Labor Warranty Duration
90 days
Warranty Provider
Manufacturer

Item Details


Manufacturer:

Model Number:

MM521 Open Box Complete-2

Weight:

4.00lbs

Internal SKU:

ls-mm521-obc6

Internal Product ID:

130961

Customer Ratings & Reviews


Polk Audio MM521 Open Box, Very Good Condition (Used) thumbnail image

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



Durability
0
Value
0
Features
0
Design
0
Usability
0

Customer Reviews

Sort by:

Loading...
Sorry, no reviews found


RMP10UB small

MTX Audio Thunderform RMP10UB (Blue, Unloaded)

Unloaded Single 10" Custom-fit Bass Slammer Subwoofer Enclosure for 1993-1997 Ford / Mazda Pickup

$254.99

List price $319.99

ZX550.2 small

Kicker ZX550.2

550W RMS, ZX Series 2-Channel Amplifier 06ZX550.2

(9)

$30.00

List price $579.99

07C88 small

Kicker C88 (07C88)

8" Single 8 ohm Comp Series Car Subwoofer

(7)

$44.95

List price $99.95

Related Searches


Save up to 10 different vehicles in your garage
Vehicle
Store
Delete

2012 Lincoln MKX

2010 Lexus IS250C

2014 Subaru Tribeca

1997 Honda Passport

1985 Subaru GL

2020 Cadillac XT6

2009 Dodge Avenger

2019 Cadillac Escalade ESV

1993 Buick Electra

1989 Mazda 626

Add vehicle Clear all vehicles
Where to find vehicle info
Are you sure you want to clear your garage?
This action cannot be undone. Confirm
This page was not designed for products.
If you continue, you will be redirected to a category customized for your vehicle. Continue
Loading...
Identify your vehicle and submodel details
  • Owner's manual
  • Vehicle's insurance card
  • Vehicle registration
  • Vehicle produced after 2005: Inside driver's side door
  • Vehicle produced before 2005: Rear passenger doorjamb, glove box, center console, or engine compartment
Car Info Side Door Icon
Vehicle Registration Icon
Vehicle Insurance Icon

Modern vehicles often require specific brackets, wiring harnesses, and mounting solutions. A fit guide ensures:

  • You see only parts engineered for your exact vehicle
  • You avoid incompatible radios, speakers, or wiring
  • Installation is smoother, faster, and frustration-free
  • You get the correct accessories the first time

Whether you're replacing a factory stereo or upgrading your entire audio system, the Fit Finder eliminates uncertainty.