The Back Magic is designed to stretch out your lower back and for me it works really well. I spend a lot of time sat at a desk and a little while ago I bent over and my back clicked; it was quite painful for a while and continues to get very stiff. I have only had the Back Magic for a couple of months, but it really helped from the first time I used it and seems to have more positive effect the more regularly I use it. I think it is even helping my posture, which is not always great when I'm working.
It's well designed to be light and easy to 'assemble' - all you have to do is slot the two bits of plastic together so I'm not even sure it counts as 'assembly'! It's easy to take with you if you go away as you can take it apart, so it packs flat. Despite being light it is sturdy and built to last.
I'm not a doctor or anything, so I can't guarantee that it will help everyone, but based on my experience I would definitely recommend anyone with lower back pain to try this.