From JUMPOW - Lumbar Back Pain Relief DeviceIf your spine is not balanced, you will inevitably have problems in your back, your neck, your shoulders and even your joints.JUMPOW Back stretcher is specially designed to improve posture and relieve back pressure. Restore the natural curvature of the back.Lightweight & compact & portable,Relieve muscle pain and stress?Function: Stretch your back and relieve stress. Let the spinal return to the natural lines and correct postural imbalances.Supportive: Suitable for herniated, compressed or bulged disk, spinal stenosis, sciatica and chronic back pain etc.Strong and hardwearing: Made of very tough ABS plastic, reliable quality and long service life. Can withstand 330lb(150kg) weight.Multi-level design: The back massage stretcher has 4 height-adjustable devices.How do you install the tool? (The instructions are in the package)1.Use your knees against the bottom and press the shelf alignment slot with both hands.2.Finger pressure on the lumber panel adjustment gently slide into the appropriate gear.Notes: The back stretcher device can bear up to 150kg(330lb).Using the device 1-2 times a day for 5-10 minutes a session.Levels 2?3and4 should only be used after you are comfotable with level 1.If you have physical discomfort and have recently had surgery or a back injury. Be sure to consult your doctor before using the product.