Comments about Staples® Poly File Jacket, Letter, Assorted, 10/Pack:
On the road & at job sites, I needed folders that were more sturdy than the typical manila variety. These fit the bill perfectly. They expand as needed, are sturdy and rip resistant, and even have a variety of colors to separate file types.
For my preference, they could even be slightly thicker / heavier...but that's not a deal breaker.