Unsurpassed Water & Tear Resistance – Superior side seams combined with Heavy Duty 100% Virgin polyethylene make these Premium Quality envelopes highly resistant to water, punctures, and tearsPressure sensitive self seal with Anti Static Release Liner – Easy packing, tamper-evident, and super secure closureLight Weight & Time Saving – Lower shipping costs combined with faster shipment preparation equal big savings over other packaging option100% recyclable