New Old Stock. The product is a box of 1000 #4 Glassine Stamp Envelopes measuring 3¼" x 4 7/8". These envelopes are made in the United States by the brand JBM and are designed to store stamps and other small items. The glassine material provides protection and clarity for the contents inside, making it ideal for collectors or individuals who require secure storage for their stamps. Each envelope is sized to accommodate standard-sized stamps and is a practical and reliable option for keeping your collection organized and protected. Free Shipping