I bought this product because the waist belt that I had used to roll down while doin excersises like sit-ups or crunches. The shoulder straps really keep the thing in place while also adding bonus upper back sweating/shaping...

I bought an XL and my waiste is a 34 my t-shirt size is a mens large and the thing barely fits... any smaller and I think the zipper would give. It is also short... I am 5'3" and when I do pull ups the thing rises to my belly button.

I would recommend the product over the commonly used waist belts..