The difference in expansion characteristics between rubber and braided stainless steel brake lines is a result of differences in hose construction. Where rubber hoses typically consist of a rubber inner hose wrapped in a textile reinforcement braid then covered in an additional rubber outer sheath, braided stainless steel hoses typically consist of a Teflon® or generic PTFE (polytetrafluoroethylene) inner hose wrapped in a braid consisting of stainless steel wire. The stainless wire braid more effectively resists expansion due to pressure inside the hose core. This in effect improves brake system effectiveness by more directly transferring operator input to brake friction surfaces. While available without a coating, the stainless braid is typically coated or covered with a clear or colored material such as PVC (polyvinyl chloride) to protect the wire and inner hose from the elements and chemicals, to protect the vehicle or machine from abrasion, and for an improved appearance. Coated braided stainless steel hoses have the same essential construction as rubber hoses in terms of an inner hose wrapped in a braid followed by an outer layer, but the different materials in the braided stainless steel hoses offer substantially different and arguably better characteristics. To more thoroughly explain why it is helpful to understand the basics of a hydraulic brake system.