Isolate your abdominal and lower back muscles with the Seated Ab / Back Extension Machine. This high-quality unit lets you perform seated back extension and abdominal crunches from the same seated position. We designed our unit with a rotary flywheel mechanism which allows for complete control over your starting position. Simply use the pop pins to adjust the pad to your desired starting position. To switch from a back extension to an abdominal workout, flip the weight post to the opposite starting position and away you go! This machine also includes (4) bolt-down holes for concrete anchors or take advantage of the counter-balance weight post for higher weight reps without the need for permanent mounting.