A pack or packet of cigarettes (also informally called fag packet in British slang; as in the idiom "back of a fag packet" or "fag-packet calculation") is a rectangular container, mostly of paperboard, which contains cigarettes. The pack is designed with a flavor-protective foil, paper or plastic, and sealed through a transparent airtight plastic film. By pulling the "pull-tabs", the pack is opened. Hard packs can be closed again after opening, whereas soft packs cannot. Cigarette packs often contain warning messages depending on which country they are sold in. In the European Union, most tobacco warnings are standardised. A patent has been granted for a cigarette package containing a container for disposal of cigarette butts. Package size Pack The size of a pack is often regulated. Government agencies usually set a minimum pack size. In Australia, the most common quantity per pack is 25, but some brands have 26 or 20 (the legal minimum), with 30, 40 and even 50 packs also sold. In Canada, most packs sold have 25 cigarettes, but packs of 20 are also popular. In many European countries, increases of cigarette tax can cause the quantity of cigarettes in the pack to change to achieve the same end price. In Malaysia, the sale of packs containing fewer than 20 cigarettes is prohibited. In the United States, the quantity of cigarettes in a pack must be at least 20, with certain brands, such as Export As, coming in packs of 25. In Ireland it is possible to buy cigarettes in packets of 33. In the United Kingdom, brands are sold only in packs of 20; in May 2017, new laws restricting loose tobacco sales to multiples of 30g or 50g also outlawed the sale of 10-stick packs and branded packaging, introducing boxes which are a plain green color. The new packaging has the brand name in a basic typeface, with most of the packet dedicated to textual and photographic health warnings. While older vending machines sometimes dispense packets containing 16 or 18 cigarettes, the dimensions of the packaging are the same as the equivalent packet that contains 20. Carton A carton of cigarettes usually contains 10 packs, totaling 200 cigarettes. Some cartons contain twenty packs, totaling 400 cigarettes. Hard pack and soft pack A hard pack is the usual style of paperboard packaging for store bought cigarettes, which consists of a relatively stable box. The flip-top hard