Hair extensions, also known as hair weaves, are lengths of real or synthetic hair that is closely attached to a person's scalp, to add length and/or thickness to the person's own natural hair. There are several different systems for attaching hair extensions, some of which last longer than others. When well matched in color and texture, and professionally applied by an experienced stylist, hair extensions are designed so that it mixes and moves naturally with a person's own hair, making it difficult to tell the person is wearing the extensions. They can provide volume, extend hair, and also add highlights or lowlights. With the proper maintenance, some extensions can last up to a full year before they need to be changed or removed.