Offered for your consideration is one (1) Polk Audio part number MW5531 5¼ inch poly cone woofer removed from my CS175i center channel speaker, USA-made in 2000.  This heavy mid/bass driver was also used in the RT15i and possibly some other Polk speakers from this production era.

So, please have a look at my large photos and read the remaining description to decide if this capable mid/bass woofer is correct for your needs.

This Polk woofer is in clean, excellent condition.  The sturdy, blue poly cone is flawless and so is the voice coil dustcap.  Plus, as with most Polk woofers, the cone suspension is permanent rubber instead of the decay-prone foam found on other brands.  In addition, the black enameled steel basket is in great shape and so is the galvanized bell over the double-stacked video-shielded magnet structure.  Lastly, the +/- terminals are keyed for polarity (red dot side is positive) and have never been soldered on the spades. It’s an exceptionally well-preserved driver overall.

Most importantly, it’s been fully tested and sounds great—fast, detailed midrange and strong bass for the platform size.  Plus, I tested its DC resistance at 4.1Ω, consistent with a nominal 4 ohm driver rating.  Lastly, the basket measures 5¼” across, 5⅞” from corners, it stands roughly 3½” tall, and the mounting holes are spaced 3⅞” adjacent / 5¾” diagonal, c-t-c.  With the flange gasket mounted, the diameter is 6⅛”.

This is a great find if you have a blown or damaged mid/woofer in your CS175i, RT15i, or other Polk Audio speaker that uses this pattern 5¼” driver with 4 ohm rating.

  As pictured and described, this Polk Audio MW5531 woofer is offered at a competitive price.

I encourage interested parties to ask any questions they may have about this listing before committing to purchase. Payment is due at checkout by PayPal or other accepted methods. U.S. mailing addresses will pay $13.95 for very carefully packed shipping via U.S. Postal Service or FedEx with tracking and delivery confirmation. International purchases will be shipped by U.S. Postal Service Global Priority Air Mail. Thanks for looking!