Halloween Ghosts Poly Mailers 6x9 Pack of 50 Unsurpassed Water & Tear Resistance: Superior side seams combined with Heavy Duty polyethylene make these High Quality envelopes highly resistant to water, punctures, and tears. Pressure sensitive self seal: Easy packing, tamper-evident, and super secure closure. Light Weight & Time Saving: Lower shipping costs combined with faster shipment preparation equal big savings over other packaging option. 100% recyclable