The cages are meant for heavy duty use in forestry and wildland fires. So are the raised chassis, off-road tires, heavy duty offroad bumper, winch, etc. Its a method of keeping trees, brush, etc away from the truck as crews need to operate the truck through these types of vegetation in areas that are densely wooded and it might damage the body, lighting, glass etc of the truck. Ive included some pictures for examples for you. Please also note I stated above the "brush cage" will be an "extra" so you can play with it or without it. This pack of trucks is meant more for the county area of the map ergo the off-road packages on them so at times youll need the brush cage. Especially servers running the Redwood Forest mod for realism and protection against driving through those environments.