Zero-pressure cushion shapes was scientifically determined with pressure sensors. The use of medium-density injected urethane foam offers both the firmness and flexibility required to obtain the desired levels of comfort and stability during positioning. The surface has a dispersion foam covering. The cushion shapes are molded to reduce pressure on bony prominences (ischium and coccyx) and to ensure controlled weight distribution over the entire cushion surface. The ischial ridge effectively helps to prevent the pelvis from sliding forward (backward tilt) and provides lateral support for better postural balance.