OEM Quality Park open-end envelopes, sold in a box of 100. These envelopes feature a patented release strip for easy opening and a convenient Flap-Stik closure that does not require moisture to seal. Made from DuPont Tyvek, they are much stronger than traditional paper envelopes, providing enhanced security against ripping, tearing, or puncturing. Additionally, these water-resistant and moisture-resistant envelopes are lightweight, helping to save on postage costs.