The yellow ones are about 10X14 and are stiff cardboard. I have about 50 of these.
The white ones are 9X12 and are strong white paper. I have about 80 of these.
Both used to seal up without tape but I suspect you'd need to tape many of these to make sure they're secure.
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2 kinds of envelopes, by the dozen (Burlingame, CA)
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