A rotary valve for controlling air supply in an inflatable device comprises a first rotor (11) and the second rotor (12) driven by motor (13) with a drive pulley (14) fixed directly onto its drive spindle (15). A toothed belt (16) driven by the drive pulley (14) engages with the toothed perimeter profile of the first rotor (11), to rotate rotors (11) and (12) relative to a stator (10). As the first and/or second rotor(s) are rotated, channels and ports on the airtight interfaces between the rotors (11, 12) and the stator (10) are connected and disconnected as required by the desired inflation sequence, including all the ports sealed in one position or all the ports exhausting to atmosphere in another position. The valve can be used in conjunction with any type of inflating device, where complex porting or air routing is required, the valve achieving this in a simpler manner.