Magic Back SupportTPR Soft Stretcher Board ,Three Level Streching Device for Lower/Mid/Upper Relieve Muscle Tightness， Lumbar Massager

Which magic back stretcher is best to use on upper back?

Is it easy to slide the device level from level one to two or to 3? About: Refresh Neck and Back Stretcher Board,Three Level Back Streching Device for

What is the material of this waist plate?

can this support someone who is 255 lbs (asking for a friend ;) )?