Columbian #10 Security Envelopes, 500 Pack, Double Window Self Seal Envelopes for Invoices, QuickBooks Checks and Business Mailings, 4-1/8 x 9-1/2 Inches, Durable 24 lb White Paper

Good material, glue works fine to seal, size is as published.

They were exactly as pictured

I love these envelopes with the self-adhesive flaps. These are impossible to open once sealed, without signs of tampering, unlike glued flaps that can be opened with water or steam. (The side flaps and folded-up bottom appear to use the same type of adhesive.) The security lining is just what you would expect, no problems there, although they may not be secure enough for top secret communications. The double-windows make them perfect for things like invoicing or anything you can print on paper and not have to worry about printing on the envelope or separate labels.

These envelopes come with a double window along the left side, so make you check your invoices to make sure that they will align along the right side. The adhesive strip is a huge plus, but it does add trash so no option is perfect. The interior of the envelope has security patterns to help decrease the visibility of your contents. The only critique is the paper used to make the envelopes is a little on the thin side which just makes it feel a little flimsy, but not so much as to be a concern of quality.

Products were fine, but boxes inside boxes had crushed corners.

I got this Columbian #10 Double-Window Security Envelopes, 4-1/8 x 9-1/2 Inch, Self Seal, White, for Mailing Invoices, Statements & Documents, 500/Box (COLO338) because it’s the size I normally use and can’t get them locally in bulk. These envelopes have a good security feature keeping your information private. The adhesive closure sticks well, just remove the cover tab and press securely, it sure beats lick and stick envelopes. Standard paper fits well, I fold mine into thirds. The envelopes seem to be a good durable paper and were put together well.

Putting these envelopes through an inkjet printer worked fine, but the heat from our laser printer melted the clear window film just enough to make them unusable.

These envelopes are pretty good quality. The windows line up correctly and I like how there is a peel adhesive to them. If you don’t like licking letters like me, then these are great since you just peel it off and stick it down. I put the letters up to the light and they are kind of see through. So if someone really wanted to try and see if you had a check or something in there, they would be able to see if they put it up to the light. Overall they’re normal and decent quality envelopes.

Excellent product.