Duffels are rectangular bags with handles and typically a shoulder strap. Duffels are often made of nylon or leather and used for short trips or commonly used as a Gym Bag.
About Luggage:
Luggage is any number of bags, cases and containers which hold a traveller's articles during transit. Types of luggage include Suitcases, Duffel Bags, and Tote Bags. Today many types of luggage have wheels as an added convenience.
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