2 Pack Stretchable Book Sleeve Covers, for Paperbacks Hardcover Textbooks up to 9" x 12", Office Supplies with Free Sticker Labels (2 Pack, Black)

I use this one for most of the standard sized Folio's (I did end up cutting off the strap): https://www.amazon.com/dp/B0FDKZ3VP2 The leather ones I bought years ago but fit similar to the cloth one above. I sometimes use these cheap, disposable ones for odd size books (I also cut the elastic at the spine if they close too tight): https://www.amazon.com/dp/B07WTTSNMR