The terms special edition, limited edition, and variants such as deluxe edition, or collector's edition, are used as a marketing incentive for various kinds of products, originally published products related to the arts, such as books, prints, recorded music and films, and videogames, but now including clothing, cars, fine wine, and whisky, among other products. A limited edition is restricted in the number of copies produced, although in fact the number may be very low or very high. Suzuki (2008) defines limited edition products as those “sold in a state that makes them difficult to obtain because of companies limiting their availability to a certain period, quantity, region, or channel". A special edition implies there is extra material of some kind included. The term is frequently used on DVD film releases, often when the so-called "special" edition is actually the only version released.