You will need this tool for any of the newer 41mm O.D. bottom brackets; in my case a new Shimano Ultegra BBR60. The tool fits snug to the bottom bracket and allows you to properly torque with a 3/8" drive torque wrench.
I bought this to install Shimano Ultegra 6800 and XT8000 bottom bracket cups, which have a unique spline pattern. Like all Park tools, this is a solid piece of work. However, you need a 38 driver to use it, and I'm not sure it works substantially better than the plastic adapters that Shimano ships with their bottom brackets. Overall, this tool is another unitasker that costs more than the component and will be obsolete in 2 years when the component design changes yet again.