Some riders want a durable brake so they pick up a metal brake. For those riders who want a lighter option, Root created the Root Industries nylon brake, which saves weight and looks cool. There were scooter brakes and then there were fenders. So, which should you buy? Easy, if you want to be able to stop, pick up a brake, which you can actually press down on with your rear foot to stop your whip. If you don't want that rear brake to inadvertently stop your wheel when your foot hits it on a big landing, you want a fender. Please note that a fender does not function as a brake and will not stop you. In other words, you're going to wear out a lot of shoes. The Root brake is a plastic brake that works with the following wheel diameters: 100mm,110mm,115mm,120mm and the following wheel widths: 24mm,26mm,28mm,30mm. Should you purchase metal or plastic brakes? It depends. If you are looking for the lightest possible setup - go nylon or plastic. If you want a durable brake that's going to last a long time, pick up a steel brake.