Quality Park Reveal-N-Seal Double Window Invoice Envelopes - 9.5 x 4.125 Inches, Self-Seal Business Envelopes for Bills, Statements & Mailing - Perfect for Offices, Accounting & Professional Correspondence

My attention was first caught by the patent number, US 6,732,494, printed inside the flap. I have been doing a lot of patent searching lately, so I immediately looked up the patent. You can also do this very easily. Go to Google Patents and enter the patent number.About the envelope: I have used similar envelopes with self-sealing adhesive in the past. I live in a very humid climate. We have had nearly sixty inches of rain in the last twelve months. The old lick and seal envelopes seal themselves and become unusable in a very short period of time.All of the press and seal envelopes that I have tried previously require that you peel off a strip before the adhesive is exposed. With the