Trolley bags come in a variety of sizes, but here are three common sizes

1. Cabin trolley bag: This is the smallest size of trolley bag and is designed to be carried on board airplanes as cabin luggage. Cabin trolley bags typically have a maximum size of 56cm x 45cm x 25cm.
2. Medium trolley bag: This is the middle size of trolley bag and is ideal for short trips or as a carry-on bag for longer trips. Medium trolley bags typically have a size range of 60cm x 40cm x 30cm to 70cm x 45cm x 35cm.
3. Large trolley bag: This is the largest size of trolley bag and is suitable for longer trips or for packing a lot of items. Large trolley bags typically have a size range of 75cm x 50cm x 35cm to 80cm x 55cm x 40cm.