posture chair approved by a uk chiropractic doctor ratchet back height adjustment with twist adjustable lumbar contoured foam seat and back for extra comfort 3 lever mechanism polished chrome base gas lift tested up to 150kg seat depth 470mm seat width 480mm seat height 400 500mm back heaight 480 530mm back width 460mm overall chair width 650mm overall chair depth 590mm overall chair height 880mm arm height 650mm