Knockerball is a 7v7 co-ed game played in the bubble soccer suits. Games are two 20-minute halves with a brief half-time period. Teams must have at least 2 girls on the field at all times, but may play with more if they choose. Teams are not allowed to have more than 5 guys on the field at 1 time. Teams do not utilize a goalie. Teams are recommended to have extra players on the team to sub in and out of the game as needed. Only molded cleats are allowed for outdoor leagues.