XMark 45 Degree Ab Back Hyperextension XM-7609 The 45 Degree Ab Back Hyperextension is hailed as one of the best lower back exercisers. Build a strong lower back and also tighten the glutes and hamstrings while strengthening the core. Constructed of 11 gauge 2 x 3 steel, dual 8 x 4.33 oversized, vinyl-covered roller pads with chrome end caps and a height-adjustable, extra-thick 3 split cushion for comfort and support. Also features tricep dip handles, a wide, horseshoe-shaped base to aid in stability, transport wheels and a scratch-resistant, baked powder coat finish. Build a strong core foundation allowing you to lift heavier weights, run at maximum capacity or perform simple everyday tasks with less risk of injury.