These heavy duty shafts replace the stock aluminum shaft. The center skid shock mounts to the rails via this shaft, and there are a few design flaws with the stock shaft.
First off some people have actually bent and or broke the shaft. To address this my shafts are made from a 304 stainless.
Second, the stock aluminum shaft is prone to wear from the center shock. Photo below shows a worn shaft. I experienced this first hand on my Sidewinder and Yamaha denied warranty replacement. The 304 stainless offers greater durability against wear.
Thirdly, the stock shaft is secured with a long through bolt. Longer bolts are prone to more stretch over time. They will torque fine initially but over time as bolt stretches it will loosen up. If not detected the rails get egged out and results in a more costly repair. The BOP shaft is drilled and tapped on each end and does away with the long bolt.