I have toppers that I never installed and/or that did not go with a trade/sale that I need to get rid of. They are:
24 by Laseriffic - $100 shipped drooped to $80 shipped!!!
It came off of a 24 that I traded and the other party did not want the topper. It worked just fine on the machine. The "feet" would need new velcro, but other than that, it should be plug and play.