The CB-13 Valor Fitness Back Extension allows the user to focus on stretching muscles while exercising muscles. Great exercise to build-up lower back muscles. Performing a reverse sit up strengthens the lower back muscles which usually are forgotten and then back pain sets in when they are used to much in such a short time. Steel frame measuring: 2" X 2" 12 Gauge Steel. 2 Contoured High density, dual-layer pelvic pads for comfort. 9 position Support Pad Arm. 3 position calf adjustment bar catch for correct support. Locking pull-pins for adjustments. 3 Rubber base caps.