These envelopes are made of pliable yet damage resistant plastic. They are perfect for standard sized documents and papers. Each one has a rectangular certified hook and loop closure the ensure tight closing and easy opening. Use them to sort and protect your documents against bending and tearing. Stay organized by color categorizing your papers with this multi-color set! Details: Assorted colors 9.75" x 13" overall size Sides expand up to 2" Fits standard sized sheets of paper 12 envelopes Hook and loop closure Plastic