Blue Summit Supplies Security Catalog Envelopes, 6" x 9", White, Self Seal, 250/Pack

They work great!

Great quality product for a great price. We have used tens of thousands of these and are very happy with their design, quality, and price.

Best 6x9 I've tried

The security feature is nice, good consistent paper quality, the sticker peel sticks out making it quick and easy to tear off, they come folded so they fold back again easily, work great in the printer, the glue seems solid.

Excellent quality, good price

Finally I found an alternative to Office Depot's envelopes which have turned for the worse. Much better quality and much better price. These are the best of those I tried from Amazon.