Roho Contour Select Cushion 20 W x 18 D Wheelchair Transport With a max output of MSHQ SK550LPP With a max output of 137 db Power: AAA Batteries (not included) 20 X 18 * The contoured design combined with the simple operation of the ISOFLO© Memory Control unit offers provides a new level of postural control and stability that has never been achieved in an air cushion * The contoured design positions the pelvis back in the wheelchair and centers the individual comfortably in the middle of cushion * The ISOFLO Memory Control unit locks air into each of the four compartments providing stability by minimizing side to side and front to back motion * Adjustable to individual s shape and weight * Cushion is adjustable to changes in individual