I recently purchased the SportLine Walking Back Support Belt not for use of support while walking, but for the thermal properties to aid in shedding excess water around my waistline.
The belt is neoprone with a rubbery inside layer. Closure is velcro to ensure it fits a wide range of waist sizes. It is light and comfortable to wear. It is not obstructive of movement, although that may change with tighter fittings of the belt.
I put it on and just did my normal daily activities, and boy did it get warm under that belt! Even just sitting at the computer I had a light sweat around my waist. I was able to sit, stand, walk, and even do aerobics wearing this belt without any discomfort or feeling I was restrained.
It does not provide a ton of support for the back, the tighter you make it, the more support will be available, but this is not a product that will provide ample support for those with moderate to severe back issues. This seems to be directed at people with decent back health looking for more support and water loss around their core.