Jackets are an important part of men’s outerwear in the Western world; they are also known as sports jackets. Jackets are buttoned up at the front and have a collar which lies down flat (lapels), somewhat similar to shirts. Jackets come in many variants, for example with a single or double row of buttons and either a central single vent or two side vents. Combined with a shirt and tie, a jacket can be worn either at the office or on formal occasions. It is also suitable for leisurewear, if worn with casual chinos or jeans in combination with a polo shirt or a t-shirt.