If you're looking for a replacement brake for your Fuzion deck, the Fuzion Nylon brake is perfect. This brake is compatible with 100mm, 110mm, 24mm, and 26mm wheel diameters, so you can be sure it will fit.
Between brakes and fenders, the choice is simple. Brakes will allow you to press down and stop your whip, while fenders won't provide any stopping power. Fenders will help keep your wheel from accidentally stopping when you hit it on a big landing, but you'll wear out your shoes if you want to actually stop.