How do you wrap/bag matted photographs for sale?

What is your preferred way to wrap matted (but not framed) photographs for sale? I’ve been using Krystal bags because that’s what my local art supply store had in stock, but I know there are many other options.

In particular, what material do you prefer to use & why? I know that Krystal bags are made from Polypropylene, but that PrintFile bags are made from Polyethylene.

I’ve also seen Polyester, Cellophane, and Acetate are also used. What do you prefer and why?

brown craft paper

Probably one of the most common product are these crystal clear bags we carry: Protective Crystal Clear Bags | Frame Destination
We carry the thicker version because most of our customers are adding some foamboard in the bag with the photo to hold it straight so they will sit vertically in bins at art shows and galleries.

I use stuff from clearbags.com (e.g. https://www.clearbags.com/industry/art-photo-packaging). (No affiliation other than as a satisfied customer).

In addition to the usual bags with flaps that seal, they sell bags without flaps.. I much prefer the flapless bags but I am not selling prints in a retail environment where the ability to seal up a package has real value.