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#10 Double Window Security Envelopes, Self Seal, 500 Count

4 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 closure is quick and easy to use without any need 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 peel and seal #10 envelope to keep your documents safe and secure behind a strong 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.


#10 Double Window Security Envelopes, Self Seal, 500 Count

Part #: BSS-92588-003

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 double window 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. For envelopes that can be used in a mail machine, you’ll want to use a gummed seal envelope.
  • This envelope is not suitable for printing in a laser printer, as the heat will melt or warp the windows.
  • While this envelope will work with QuickBooks invoices, it is NOT suitable for sending QuickBooks checks, as check information will not line up properly in the windows. Please click here for envelopes suited for mailing QuickBooks checks.
  • 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-92588-003
  • Barcode: X001AZ4VOV
  • Package dimensions: 11.9 x 10.1 x 4.4 inches
  • Package weight: 6.25 pounds
Customer Reviews
5.0 Based on 4 Reviews
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Richard G.
United States United States
My Mistake

Hello Blue Summit Supplies, There was nothing wrong with anything from your side. The envelopes are great and the delivery was quick. This issue is that I make a mistake and order the wrong size envelope. I order a #10 envelope when in fact I should have order a #9. Thanks for following up. Rich Graham American Food Service Depot

Andrea S.
United States United States
Quick and Fast--We like that!

The information to order was clear and concise. The order arrived quickly and cost less than going to the "big guys". Thank You!

jinie p.
United States United States
Good envelopes

The envelopes were exactly what I expected. It works well for sending out statements. Price was reasonable. Very convenient.

Karen S.
United States United States
Love It

They always arrive on time and always what I need