Rotor designed the BB30 BB24 Converter Mountain Bike Bottom Bracket to make changing components between frames a breeze. Now you're able to use the 24mm cranks of your choosing with that BB30 frame. Rotor created a smooth, aftermarket converter using its labyrinth seals. Labyrinth seals have a series of grooves, or teeth, where the male and female pieces slip together often perpendicular to the threads. These grooves create a maze that fluid would need to pass through in order to create a leak. Additionally, the labyrinth seals provide unparalleled protection from elements such as dust, water, and mud. Most importantly, though, this converter allows you to run a conventional BB24 crankset with a BB30 frame. And even better, at around 120 grams, it allows this without stacking up needless weight. The Rotor BB30 BB24 Converter Mountain Bike Bottom Bracket is compatible with conventional BB24 cranks from Rotor, Shimano, and Shimano compatible brands. It features steel bearings, and it's available in the color Black.