Gym bags are rectangular bags with handles and typically a shoulder strap. Gym bags are often made of nylon or leather and are typically used to carry needed items to a gym for a workout. Gym bags may also be referred to as duffels.
About Zipper:
A zipper, sometimes called a 'slide fastener' is a device consisting of two toothed tracks or spiral metal or plastic coils, each bordering one of two edges to be joined, and a piece that either interlocks or separates them when pulled.