1.EXPANDABLE & HIGH CAPACITY-The file organizer keeps each slot's papers separated and organized in a good manner. 2.PORTABLE & SECURE DESIGN-The accordian folders full-size flexible flap and cord closure provide added security. To access stored items, simply fold back the flap. When finished, return the flap up and over the top of the folder and secure it in place using the cord closure. 3.STABLE & WATERPROOF MATERIAL-Our alphabetical accordion folder is made from high-quality polypropylene (PP) plastic material (nontoxic and nonradioactive), which is environmental and friendly, also not easy to break or deformation. Waterproof and moisture-proof material can keep your important documents clean. 4.WIDELY USE- Our expanding file organizers are suit for organize utility bills, invoices, letters, A4 paper and other documents. Suit for school, office, home use, or as good gift for teachers, students, doctors, engineer, designer, researcher, salesmen etc