Fencing materials are plain or decorative partitions used to prevent access or contain a property or facility. There are many different types of products. Examples include chain link fences, ornamental fences, picket fences, vinyl fences, and wood fences. Before installing a fence, certain factors must be considered including style of fence, privacy, security, and landscape enhancement. Product specifications include dimensions and materials of construction. Chain link fences consist of four elements: fabric, framework, fittings, and gates. Fence components are available in a variety of weights and protective coatings. The most common coating for a chain link fence is galvanized zinc; however, chain link fences are also coated in vinyl or polyester. Ornamental fences are available in many different types. Originally, these fences were designed by blacksmiths and made from wrought iron. Today, ornamental fencing is usually made of steel or aluminum. It is fabricated into sections with fasteners, locking rods, or welding. Ornamental fences can be used in securing an area if proper fence height, spacing, style, and materials are used. Picket fences are typically used in domestic or residential settings. These fences can be made from wood, or plastic that resembles wood. Picket fences can be built or assembled from prefabricated sections. The appearance of these fences is often short, with tapered or pointed tops on even-spaced vertical boards. Vinyl fencing is created to look like traditional or decorative types of fences. They use the same type of materials that are used in vinyl siding and windows. There are two types of vinyl fences: mono-extrusion or co-extrusion. Mono-extrusion fences are made from one layer of ultraviolet inhibitor materials. Co-extrusion vinyl fences have two layers, and are more resistant against scratches. Wood fencing is another popular option. Wood fences are affordable and easy to work with. When choosing a type of wood for fences, there are two important considerations: form and function. Wooden fences can be decorative, or provide privacy. They may include picket fences, which can be used to border property and for protection; as well as rail wood fences, which are used for aesthetic purposes, to mark boundaries, or to contain livestock.