Basildon Bond C6 114 x 162 mm Gummed Envelope - Airmail Blue (Pack of 20), 100080079

I have a lot of pen pals and Airmail paper is an essential.This is somewhat thicker than the old style Airmail paper or ‘Blueys’ that the Post Office used to supply, but on the flip side it enables you to write on both sides if you use a biro (not if you use a fountain pen or rollerball) and that reduces the number of sheets you need to send.Lovely and smooth to write on, classic colour.

I was looking through me mam's old letters and kept seeing these old sorta envelopes. I saw them here and now I'm using them in an art project on memories and they're just so cool

Would have liked to know the size

Not particularly thin.