We are proud to introduce POLYNET ENVELOPES made of specially manufactured POLYNET, HDPE COATED PAPER to serve your mailing needs of important and valuable documents. Our SELF ADHESIVE WATER RESISTANT POLYNET PAPER ENVELOPES have a decisive edge as a permanent replacement over conventional cloth pasted envelopes. While our HIGH DENSITY POLYETHYLENE COATED ENVELOPES ( HDPE ) are the strongest and unique.