The outside is a fabric for the Velcro to stick to, but the inside is a rubber. The rubber goes against your skin and makes you hot and sweaty in your midsection, and hip area. So it helps you to ahead all that extre water you are holding there. The only thing is once that water is gone I don't think it will help very much. However until you do lose it you get to look like you already did.
This is a very rigid belt so until you lose the muffin top it holds it in for you. So you get to look skinny while working your way to your ideal weight. I think it's great, I don't really work out like at a gym. Although me and my daughter walk everyday and I live at the top of a huge hill so pushing her stroller up it is a big work out.
I have been wearing this every time we go and I think it has helped a little bit. It will continue until my water weight is gone so I will continue to wear it.
Disclaimer: I received this product at a discount in exchange for my honest unbiased opinion of it