Delivery health (デリバリーヘルス, Deribarii herusu), also known as "shutchō health" (出張ヘルス) or by the abbreviation "deriheru" (デリヘル), is a form of prostitution in Japan similar to fashion health, "health" being a term for sexual services. The difference being that the brothel has no premises and is essentially a call girl (or "escort service") with women being dispatched to their customers' homes or to hotels.
Outcall call girl businesses distribute advertising handouts to home and apartment mailboxes, telephone booths, restrooms and the like in big cities in Japan. There are also numerous websites to find these businesses or other similar businesses.
References
Delivery health Wikipedia(Text) CC BY-SA