Since 1990, I have enjoyed collecting and restoring antique radios and vintage audio.... all items I list will be exactly as described and packed extra well to ensure a safe delivery.. buy with confidence ! BUYER is responsible for doing their own research to ensure they are buying the correct speaker/part for their application ! NO ORDER CANCELLATIONS or RETURNS due to buying the wrong, or incompatible type speaker ! For sale is a single 5.25" Mid Woofer removed from a Polk M3 II speaker. Model/Part # is MW5800. Tested and plays great. I had a pair of M3 series II speakers with a blown woofer, and gave up trying to find one of these MW5800 mid woofers, so decided to just part out the speakers... These are impossible to find! Once you carefully open up the plastic cabinet... a very gentle process to separate the front baffle section that has speakers attached, the mid woofer is removed by simply turning it clockwise... and the frame will come out of the 4 top slots that lock it into place... to reinstall this mid woofer, you simply reverse the process. Set it over the opening, then turn it counter-clockwise about 1/2", until it locks into place. It will be evident how this is installed once you open up cabinet and see how the woofer is held in place. The frame of woofer has a rubber gasket built-in that helps lock down woofer... there's 4 areas around woofer perimeter where the rubber gasket has a few tiny gouges, tears from uninstalling... no way to remove woofer without the lock pieces biting into the outer rubber gasket. Does NOT harm anything, and this will re-install just fine ! It's possible that this same model, MW5800, was used in the original, 1st version M3 model speakers but I have no way to know without finding a downloadable Service Manual that has an Exploded View of parts... Again, BUYER is responsible for doing their own research to ensure this is correct part for their speaker or application. Will be well packed for a safe delivery. BUYER is responsible for doing their own research to ensure they are buying the correct speaker/part for their application ! NO ORDER CANCELLATIONS or RETURNS due to buying the wrong, or incompatible type speaker ! Ask any and all questions BEFORE buying! After buyer has left positive feedback to acknowledge everything OK, I will immediately return the favor.