These pull up bar ab straps encourage superior toning, trimming and conditioning of the entire abdominal area without lower back strain. In fact, they can actually help a bad back by stretching the muscles and decompressing the spine. Features include solid steel Fire and Rescue Locking Carabiners that are rated at 10,000 lbs. capacity each. Arm slings are 8 1/2in wide with dense and durable 1in thick pads.