Our ripstop Polyurethane fabric stands up to nonstop travel. It is ultra lightweight and durable and as well as being more reliable than even nylon alternatives for packing cubes. Additionally, polyurethane fabric is water resistant to help keep moisture out of your clothes wherever they're packed. Zipper on the packing cubes all have reinforced zipper stops. Zippers used for expanding/compressing function of bags have been reinforced with double stitching as well. Total 4PCS: Small 30X20CM Only 1 Medium 35X25CM Only1 Large 40X30CM Only 1 Shoes Bags Only1 EASY TO USE! Compression packing cubes help you with packaging your clothes for upcoming trips by compressing the air out of them. These are not your typical vacuum bags-these expandable cubes use a two zipper system to help eliminate the extra bulk when packing your luggage. The zippers literally compress your clothes together and eliminate wasted space. Skip the extra fees of a checked bag- eliminate the bulk and use a carryon instead!