*PREMIUM QUALITY ENVELOPES. Have a good stretch, lightweight and water-resistant. Lower the shipping cost of your business and protect your products on the rainy or snowy day. *TEAR RESISTANCE SELF SEALING ENVELOPES. The adhesive on the fold-over flap is really strong and tamper-evident. There's no need reinforcement tape and it doesn't come apart unless you tear it up. If you are tired of plain regular mailers, our DESIGNER POLY MAILERS are a choice for you.