My car seats don't have lumbar support and are often very painful to sit in. I went to REI and bought a Thermarest Lumbar pillow. It inflates so I can easily adjust it to the width I need. I also rolled it up and put it in my purse so I could use it any time I was sitting for a time such as plays or concerts. I also used it under my knees or between my knees for sleeping. I still use it in the car.