The Sweet Sweat Waist Trimmer was designed to be worn during exercise. The trimmers contoured fit and flexible neoprene allows for a full range of motion during your workout. Remember not to wear the belt too tight, as this can actually hinder circulation and range of motion during exercise. Premium Quality Makes The Difference Forget those cheap, thin ab belts! The Sweet Sweat Waist Trimmer is made with the highest ge Neoprene for Superior heat insulation and lasting wear.