Inspired by NASA technology, the Zero gravity position is the perfect position to enjoy a massage, aligning your back relative to your thigh at an optimal level of comfort. When reclined into the zero gravity position, the complete weight of your back is virtually supported by the backrest which maximizes the intensity of the massage. This feature improves spinal decompression and decreases muscle tension of the spine. There are 2 stages of zero gravity, the 2nd being more reclined. When reclined fully, to where your legs are higher than your heart level, the therapeutic effects are incredibly effective and may be felt immediately. Osaki OS-4000T has re-engineered and has developed the next generation of air massage technology, streamlining the air massager to a lower count.