With its 3D ventilation, your breathable back pillow for sleep allows constant, refreshing airflow inside, the soft top surface won't get hot or soggy like memory foam. offering a cozy and comfortable sleeping environment for a good sleep. SIZE: Measuring 46X20.5X8cm, the total thickness could be adjusted by adding a 1cm detachable roundel to help improve spine posture. It reduces strained back muscles and ligaments in the supine, side, and stomach sleeping positions, also can be placed in the calf or between the knees as a leg spacer. The unique open weave Air mesh material used in our back support pillow makes it extremely hygienic and durable, with no chemical smell or odor. It is not recommended to wash the pillow core with water but put it in the Sun.