Union produces a health-positive result through the manifestation of the BioFlex Shell technology, which automatically responds to the sitter's seated behaviors with carefully programmed micro and macro flexion initiated by subtle shifts/movements of the sitters body mass. This instinctive response of the shell supports a range of postures that include active postures (hand tasks in forward leaning postures) to passive postures (passive tasks, reclined/relaxed posture), and every posture in between.