Featherweights are a class of fighting robot that are particularly popular in the UK and Europe. They follow the Fighting Robot Association build rules and have a weight limit of 13.6kg[(http://www.fightingrobots.co.uk/rules.php)].
Every year they compete in the Featherweight Championship (held by RoboChallenge for the last couple of years) to attempt to become the Featherweight Champion.