http://speakerpage.com/S10142.htm

Check out the specs, they're an ideal mate for the PS-10 enclosure, cheap ($35), and made a VERY nice improvement in the bass response. However, I had to make 1/8" spacer-gaskets to go between the woofer and the enclosure, as the magnets were just a tiny bit too big to clear the cardboard tube behind the midrange. I also used T-nuts with screws to hold them securely, instead of the cheapy stock wood screws, which never really held well in the particle board cabinets. I took a bunch of digital pictures of the whole process if you're interested...