This functions well as a portable book stand. It's lightweight, folds flat and can be put in lever arch files with 2, 3 or 4 holes. It is too large for ordinary ring binders.It can hold pretty thick books - say around 600 pages, depending on whether it's a paperback or a hardback, but unless the book is reasonably good at staying open itself, the page holders won't hold it open, although it can hold a few unruly pages.The angle at which the book is held can be adjusted from about 60 degrees to maybe 20 or 30 in eight increments (sorry - no protractor!). Adjustment is made by inserting a tab into holes in the prop at the back. I would prefer another steeper angle, myself. There is another 'slot' that can be used for this, but I don't think it's mean to be - it's awkward to get the tab into it.The construction of the stand leaves something to be desired. The six pieces click into place, and when being adjusted, opened or closed, any of the parts can come off, which is annoying, although they do easily snap back into place. However, in use, it is rigid enough, except for the page holders, which may come off when moving them to turn the page or when holding books that won't stay open themselves.When I bought it, I did feel miffed at the high price of the postage, but I wanted portability, and this does provide that in spades. Most other book stands are too heavy or unwieldy.To conclude, I'd recommend this if you need to take a book stand with you, otherwise, you might want to consider other designs.