Just right!
I've tried book covers in other fabrics over the years, but these are the best. They stretch to fit variations in sizes, but flex with the book when open. The 4" fits a standard paperback, the 6" fits a trade paperback. The 6" will also stretch to fit a hard cover, but it is snug. The creator has expressed a willingness to make custom covers to fit. I highly recommend.
Rating: 5 stars