I got mine from Jusco, it has a boned panel at the back and 2 straps which you can velcro together. The 2 straps will rest on the top and bottom of your belly, I have a long history of sciatica, so I understand the pain that you are in. There is any type which wraps around your belly, I was told by the sales lady that the one with the boned backing is better at alleviating back problems. But it is definitely not going to solve your back problem, it will make it more bearable.
Having a hot water bottle and walking definitely helps me with my back pain more the belt.
Good luck!