I buy the clasped envelopes because the ones with no clasp and the same size cost almost twice as much which seems to me pretty DUMB. I would much rather have 9X12 manila envelopes without a clasp. Why in the world would they cost more? Makes absolutely no sense to me.
Sturdy enough for every day use. We do construction and the guys are always wadding up our receipts. I use these to keep the job receipts organized. They stand up to those roughnecks!