Spare sidewall for the "Palm Beach Beater" 1 pound beater bar kit. The kit is designed to be serviceable and budget friendly to repair. Odds are the sidewalls are the only piece that will need replacing after a big fight. Pro tip, if it's just bent and not completely destroyed you might be able to use a heat gun and bend it back in to shape and keep going.
Spare sidewalls are sold individually. There are 2 required per robot and are interchangeable from left/right.