Late 1880's Health Bustle
This bustle dates to about 1887-1889, but continued in a slightly smaller size until about 1911. It is made out of criss-crossed wire, which was thought to allow your back to "breathe", thereby eliminating fainting. In fact most women just wore it with their old bustles to bulk up the size making their backsides even bigger!
Ironically, they were worn by themselves in the 1890's to Edwardian times to give the skirt a slight rise in the back and to stop the skirt from sticking in between your bum.