Using a zipper to close a bag is as easy as it gets. Several different materials have been used to make this bag, including polyester.
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Targus Citygear notebook case 43.9 cm (17.3") Backpack Black
The product is available from £30.08 at international stores.
CCL Computers AMD
Targus CityGear 15 - 17.3 inch Laptop Backpack, Black
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