In addition to the tech requirements listed above plastic sliders are recommended for the rear axle, footpegs, and bar ends or handgards. These are required equipment this season for AMA Pro Supermoto and will be required for the amateur classes next year. A gouged up track means the promoter won't be so eager to have the bikes back again.
There are different brands starting to show up on the market, here is a picture below that shows typical sliders for rear axle, pegs, and handlebar ends.