Sizes XS is designed with double elastic bands for the perfect compression of your choice. It does not expand.
Sizes M and S, M, L, XL are the evolution to achieve the perfect compression according to your body type. Here you can adjust exactly which part of the midsection you are targeting.
This belt shapes the waist, it does NOT burn fat or make you lose weight. If you ever hear of a belt (with or without gel) that is supposed to burn fat, beware: this is fake marketing. No belt burns fat. Sorry to tell you.
We do not recommend wearing this belt tight if you are new to the item, you may give up too soon. Wear it not so tight at first, and then day by day you can slightly tighten
The interior material is neoprene to avoid any skin irritation.