Ergonomic design, this ergonomic seat cushion has a slow rebounds memory foam, which provides you with firm and keeps shape, and has a longer service life Our cushion has a thickness of 3.5inches and can be used as a seat lift, providing a few inches of lift to improve your perspective The inner core cannot be washed with water and can be placed in a ventilated place to dry The pillowcase can be washed with water The large opening zipper design makes it easy to remove the cover for cleaning Even in hot weather, breathable fabric can keep you cool Multi purpose seat cushion: memory foam seat cushion is thinners in front and thicker in the rear, and the front of seat cushion gradually becomes thinners to 0.6inches belows the legs to pressure under the thighs It can also be used as a lumbar pillow to fill the corner between the lower back and the seat backrest, alleviating lumbar caused by prolonged driving