Unlike airlines, most major cruise lines (such as Carnival, Royal Caribbean, and Norwegian) do not have a strict "per-bag" fee, but they do have guidelines for weight and safety. The standard recommendation is two bags per person, with each bag weighing no more than 50 lbs (23 kg). This weight limit is primarily for the safety of the porters who handle thousands of bags in a single afternoon. However, the most important "restriction" isn't weight, but content. You are strictly prohibited from bringing items with heating elements, such as irons, kettles, or candles, due to fire risk (though hair straighteners are usually allowed). There are also complex rules regarding alcohol: most lines allow you to bring one or two 750ml bottles of wine or champagne per cabin during embarkation, but beer and hard liquor are generally confiscated and held until the end of the cruise. All luggage is scanned via X-ray, similar to airport security. It is also highly recommended to carry a "day bag" with your essentials and medications, as it can often take several hours for your checked luggage to be delivered to your stateroom after the ship has set sail.