Waist training corsets are steel-boned corsets designed to slim the waist and "train" it to a certain size. The size varies depending upon the wearer's goals.
Training corsets have been used for centuries to train the waist of women and sometimes of men or boys. Gradual tightening of the corset and long-term wear compress the soft tissue of the waist area and push the floating ribs upward to make the waistline smaller. Beginners choose a corset 4 or 5 inches smaller than their natural waistline and begin wear to break in the corset and allow the body to grow accustomed to wearing it.