S4, SB3, SM4 are disability swimming classifications used for categorising swimmers based on their level of disability. Swimmers in this class have coordination problems affecting all four of their limbs, with coordination problems being more severe in their legs to the extent they may have limited to no use of them. They also generally have no trunk function and weakness in their hands and arms. A variety of disabilities are represented by this class including people with cerebral palsy. Events this class can participate in include 50m and 100m Freestyle, 200m Freestyle, 50m Backstroke, 50m Butterfly, 50m Breaststroke, and 150m Individual Medley events. The class competes at the Paralympic Games.