Not everyone wants to run the stock Rotor crank on their BBright equipt frameset, in fact, most people really just want to run a complete Shimano group including the Crankset. Rotor knows this and they made the most robust adapter out there. The BBright to Shimano adapter presses into the frame and allows you to run a 24mm Shimano crank instead of the 30mm Rotor crank.
Rotor created an all inclusive system. This adapter is everything you need with the exception of the crank and the tools to install it. The bearings are top quality and the fitment is perfect every time. Bottom brackets these days can be very confusing fortunately this upgrade is a no brainer.