Single track zipper extends the width of the bag and keeps products clean and free from moisture No labels needed. Large write-on block for descriptions, quantity, pricing, etc. Use felt tip or ballpoint pen to write directly on the bag. Reclosable and reusable. Meets FDA and USDA specifications for food contact. Sizes listed are the inside usable dimensions of the bag. Office Depot (R) Brand 4-Mil White Block Reclosable Poly Bags, 3in. x 4in., Case Of 1,000 is one of many Poly Bags available through Office Depot. Made by Office Depot.