Pornographic magazines, sometimes known as adult, sex or top-shelf magazines, are magazines that contain content of a sexual nature. Publications of this kind generally contain images of attractive naked models, as is the case in softcore pornography, and, in the usual case of hardcore pornography, depictions of masturbation, oral or anal sex, and intercourse. They primarily serve to stimulate sexual arousal, and are often used as an aid to masturbation. Some magazines are general in their content, while others may be more specific and focus on a particular pornographic niche, part of the anatomy, or model characteristics. Examples include Asian Babes which focuses on Asian women, or Leg Show which concentrates on women's legs. Well-known adult magazines include Playboy, Penthouse and Hustler. Magazines may also carry articles on topics including cars, humor, science, computers, culture and politics. With the continued progression of print media to digital, retailers have also had to evolve. Apple's Newsstand is a popular version of this, but as they don't allow pornographic material, specific digital newsstands for pornographic magazines exist.