Sets include 4 or 6 packing cubes in an assortment of sizes Built-in compression zippers allow you to save space and compress height by up to 60% Exterior made with tear-resistant, water-resistant twill Mesh top window panel for visibility and ventilation Same luxuriously soft, anti-microbial interior fabric as found in our luggage lining, made with 100% recycled polyester Anti-catch zippers Lightweight yet well-structured build can stay upright when empty Stores flat when not in use Our packing cubes are designed to fit perfectly in Monos luggage (Set of Four fits all Carry-On sizes; Set of Six fits all Check-In sizes)