Protect your stuff from rain and hard bumps with a hard shell suitcase. Most hard shell suitcases are made of polycarbonate or polypropylene. These materials are strong and don't weigh much. That way, you can choose good protection without having to carry around extra weight. There are trolley suitcases with and without a zipper. Hard shell trolley suitcases protect your stuff from moisture extra well. There are also different sizes of hard shell suitcases, like carry-on suitcases, medium suitcases, and large suitcases. Choose the suitcase size that best suits your journey.