Designed to fit the contour of a standard bathtub. Seat dimensions are 15.25"D x 20" W. Vinyl grips on the tubing prevent marring the tub. Tub must be 22" wide. This measurement must be taken at the center of the tub, inside wall to inside wall, and measure halfway down the wall and across to the other side of the bathtub. Bath seats are designed for bathtub use. If you desire to use in a shower stall, you must insert the bath seat into the Model 1721 floor stand to prevent the bath seat from turning over. Capacity 650 lbs.