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#9 Windowless Security Envelopes, Self Seal, 500 Count

2 reviews

  • Durable and professional go-to standard business envelope for mailing invoices, statements, and other office mailing needs.
  • Roomy enough for a return envelope to be included, so you can get a response quicker.
  • Low-profile flap design creates a wide opening for easy and quick envelope stuffing.
  • Peel and seal flap makes it simple to close without having to lick or moisten the glue.
  • Dark security tint lining keeps your important documents securely concealed throughout transit.


We’ve designed our standard gummed seal #9 envelope to keep your documents safe and secure behind a strong permanent glue seal throughout transit. Our most popular business envelope is made from a durable 24lb white wove paper and comes equipped with a low profile flap design, which makes it easy to fold and stuff up to 10 sheets of standard letter size paper inside with room for a #8 return envelope as well – so you can make it simpler than ever for your clients to quickly return payments to you. And with our dark security tint lining the inside, your confidential mail will stay concealed and secure all the way to its destination.

Our low-profile design makes for easily printing in most HP, Epson, Brother, Cannon, Xerox, and other standard laser and ink jet printers.   It’s an envelope choice that’s simple enough for everyday letters and statements, yet professional and secure enough for even high-profile business communications.

We stand behind our products completely. We understand that buying products online can sometimes be difficult because you cannot physically see what you are buying; however, if our product is not exactly what you are looking for or does not meet your expectations, then we welcome you to send them back anytime for a 100% refund. Click here for more information regarding refunds or returns >

Key Features:

  • #9 double window envelope
  • Dimensions: 8 7/8 inches X 3 7/8 inches
  • Security lining
  • 24lb white wove paper
  • Package quantity: 500 Count


  • This envelope is equipped with a self-seal, which means it requires that you peel away the protective strip to reveal the glue. It does not require moistening, but cannot be used in a bulk mail machine (only standard gummed seal envelopes can be used in mail machines).

    Product Details:

    • Brand: Blue Summit Supplies
    • Part #: BSS-92588-034
    • SKU: BSS-92588-034
    • Barcode: X00298KZ9N
    • Package dimensions: 11.1 x 9.1 x 4.2 inches
    • Package weight: 6 lbs
    Customer Reviews
    5.0 Based on 2 Reviews
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    Filter Reviews:
    Hanna S.
    United States United States
    very good prpduct

    What I needed for my business

    United States United States
    The best #9 windowless security envelopes

    These envelopes are great and they feed through my printer without any problems.