It has been great in my car for long trips
I have arthritis in my lumbar area and purchased this to help with sitting at work. It has been great in my car for long trips, I find it much more comfortable than the larger lumbar supports.  It has a belt to hold it in place in the car but it is awkward to install on a car seat with one person.  It is not too big, it is not rigid but it is firm enough to provide support.
Rating: 5 stars