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#10 Windowless Security Envelopes, Self Seal, 500 Count

5 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 paid faster
  • 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


It’s no secret that the #10 security envelope is the workhorse of business mailings, and we’ve designed our standard gummed seal #10 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 or #9 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. 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.

Part #: BSS-92588-009

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:

  • #10 envelope
  • Dimensions: 9 1/2 inches X 4 1/8 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).
  • Don’t need that many envelopes? This product is also available in a smaller 100 count package.
  • Not sure what type of number 10 envelope is right for you? Read our blog post about #10 envelopes, wherein we help you wrap your head around every detail you never knew you needed.

Product Details:

  • Brand: Blue Summit Supplies
  • Part #: BSS-92588-009
  • SKU: 0R-7YPW-WR5A
  • Barcode: X001BLMGP5
  • Package dimensions: 11.9 x 10.1 x 4.4 inches
  • Package weight: 6.5 pounds
Customer Reviews
5.0 Based on 5 Reviews
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Filter Reviews:
    Tyler I.
    United States United States
    Wonderful service.

    The order was on time, and it had all of the envelopes stored in a box in a manner that makes them more mobile for me, and that's important for what I am doing. Excellent service on their part.

    David S.
    United States United States
    Great company, great supplies

    Envelopes were delivered quicker than expected and in "dent-proof" packaging. Each envelope was thicker than others we have used in the past, showing a higher quality product.

    Gregory D.
    United States United States
    Excellent quality each and every order

    Never have an issues with the products I purchase from Blue Summit. I highly recommend.

    Diana V.
    United States United States
    Just what was needed

    As one of Jehovah’s Witnesses our ministry is being done largely through letter writing due to COVID-19 restrictions. To find reasonably priced envelopes was a blessing

    B B.
    United States United States
    Windowless Envelopes

    They look and seem just like the ones we have been using from the Big Box office supple store.