The BodyBilt #2 seat is the most contoured seat pan in the BodyBilt seat range. The U-shaped contouring follows the curve around the back of the seat, then extends outward to create leg troughs to the front of the chair.
Those leg troughs were designed into the chair to cradle the legs – and in that process, increases the surface area of contact with the legs. The greater amount of contact area you have with the legs and buttocks, the greater area bearing the weight of the body against the chair thus effectively lowering seated pressure on that part of the body. Lower seated pressure typically translates to greater comfort.
(Note: this seat configuration has been highlighted as unsuitable for hip replacement patients)