Any Suggestions on Belly Support Bands?

Jmollo28

My Dr Suggested to wear one to support my back (I have an extra curved spine) so I found a ton of different types online.  I see one that criss crosses and straps around your chest and holds up the belly.  Another one that looks like it just straps around and under the belly.

Anyone use this or have an idea of the best kind to use?

 Also, how do the sizes run?  I see it is small/medium/large.  I'm medium normally, but my pregnancy pants I have in a large for growing.. would I do the same for the band?