The Patek Philippe Nautilus watch was released in the mid 1970s and has since become one of the manufacturer's best-known and most popular models. A luxury sports watch, with a distinctive design based on the portholes of a ship, the Nautilus now comes in a variety of different types, with varying complications and case materials. The rose gold material adds a sense of warmth and softness to the Nautilus design when compared to the original stainless steel design. It is also a more precious material, enhancing the sense of luxury, while some feel the color provides a more feminine appeal, and this has helped to make it a popular choice of material for women. Watches in this category include full rose gold watches, as well as two-tone rose gold and stainless steel watches. Black, blue and brown dial colors are available, while complications on some of these watches range from simple date displays, through to chronographs, moonphase indicators and day/night indicators.