A 4D massage chair takes the 3D robotic technology and adds in a speed variation component in order to really give you a life-life, deep tissue massage. Originally developed in Japan, engineers took an algorithm of 100s of massage therapists and mimicked their motions as they sped up and slowed down in certain areas. With a 4D chair, you have more adjustment and control at your fingertips. We have several very high-quality 4D chairs available and also now even have an L-track 4D chair.