Hardshell cabin luggage — or cabin suitcases — are made of plastic and are up to 55 cm long and up to 50 litres in volume. They are suitable for short trips or as an add-on to a normal large suitcase. Most airlines allow you to take them with you on board. Compared to cloth cabin luggage, they are tough and sturdy and provide better protection. On the other hand, they tend to be quite heavy.