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.
About Metal:
Metal is a strong, shiny material that can be molded and shaped in any way and is often used as a decorative ornament in garments and footwear.