A ball-jointed doll is any doll that is articulated with ball and socket joints. In contemporary usage when referring to modern dolls, and particularly when using the acronyms BJD or ABJD, it usually refers to modern Asian ball-jointed dolls. Many contemporary BJDs are cast in polyurethane synthetic resin, a hard, dense plastic, and the parts strung together with a thick elastic. They are predominantly produced in Japan, South Korea and China. There are also some Asian companies that have turned to cheaper production methods by creating dolls using other plastics such as ABS. As ABS dolls in particular are manufactured using injection molding rather than being individually cast, they are generally less expensive. These dolls may be strung with elastic or assembled with hinges in their ball joints. Opinion in the BJD community is divided over what does and does not constitute a BJD, with some believing a BJD must be made of resin and strung, while others take the view that any doll with ball and socket joints can fit under the BJD label. There are currently no industry standards or manufacturing guidelines governing what is or is not, in fact, a BJD. There are also BJDs made by European artists, usually referred to as Artist BJDs. These dolls are normally made from polyurethane resin, though can also be made out of a wide variety of materials such as porcelain, paper clay and super sculpey. The BJD style has been described as both realistic and influenced by anime. They commonly range in size from about 60 centimetres (24 in) for the larger dolls, 40 cm (15.5 in) for the mini dolls, and all the way down to 10 cm (4 in) the very smallest BJDs. BJDs are primarily intended for adult collectors and customizers. They are made to be easy to customize, by painting, changing the eyes and wig, and so forth. The modern BJD market began with Volks line of Super Dollfie in 1999. Super Dollfie and Dollfie are registered trademarks but are sometimes erroneously used as generic blanket terms to refer to all Asian BJDs regardless of manufacturer.