OEM Quality Park open-end envelopes, sold in a box of 50. 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 stronger and more secure than traditional paper envelopes, ensuring they won't rip, tear, or puncture. Additionally, these water-resistant and moisture-resistant envelopes are lightweight, helping to save on postage costs.