The eighteenth slot-machine booklet by Swedish Post were issued in September 1969, over a year after the ordinary booklet Wild Flowers and it replaced the Iron Age, Öland from 1967. The motif was the the bridges to the island of Tjörn west of Gothenburg on the west coast of Sweden. Unfortunately one of the bridges collapsed after a collision by a ship in 1980 and tragically caused some casualties, but on the stamp all the bridges are still standing. The bridge was later rebuilt.
The denomination was 15 öre, 30 öre and 55 öre. The 55 öre was the rate of domestic - 20 g letter, there were no longer any single use for 15 or 30 öre, but the combination 15 + 45 öre covered postcards, domestically, for the other Nordic countries and internationally.