12.5x9.5 Rigid Document Mailers Stay Flat Corrugated Envelopes LX-1 9.5x12.5 (50)

Use these to ship vintage sheet music and they work like a charm. Not a single complaint from customers. Good adhesive seal. Exactly what I was looking for. Produces lower shipping weight (and thus cost) than other methods.

Not rigid. You can bend the envelope completely in half. If you need something to not bend these will not do the trick. And shipping them to return them costs more than the actual envelopes. So, I am just out of the money.

Not very rigid. I put in an extra piece of cardboard for sending artwork.It would be fine for documents.

I got these to protect 8.5x11 prints, and they do just that, quite well. A lot of my customers appreciate it

I have ordered this item in the past and it was a bit more sturdy than this shipment.

Just what i wanted. Good quality too