A billboard (or a hoarding) is a large structure used for advertising, and is usually placed outdoors in areas where there is a lot of traffic, such as busy roads. Billboards are used to advertise products to passing pedestrians and drivers, and are very effective, due to their size and positioning in designated market areas. Billboards have many standard sizes, and the names of the billboards originate from the old days when posters were made up of a specific number of panels. Popular billboard sizes start from '1 Sheet' which is 508mm x 762mm, and one of the largest is '96 Sheet' which is 12192mm x 3048mm (40ft x 10ft). The largest standard sized billboard is known as a Bulletin, and is 48ft x 14ft.