This body contouring waist trainer compresses the stomach and generates heat to burn extra calories. It is an excellent addition to body contouring as the pressure also stimulates your lymphatic system and your body will eliminate the waste faster. It is one size fits all and is adjustable so no need to replace it as you get slimmer. The elastic is very high quality and won't deform over time. This should be worn right after your non-invasive treatment.