NUOBESTY 10pcs Plastic Slide Book Binding Clips - Loose Leaf Sliding Bar Binders for Books, Folders & Reports - Secure Document Organizer for Office, School & Home Use

I like to use slide-on binder bars for various projects, but the thing I use them for the most is when I create and print my own LEGO instructions. So far with these, I am using one on a booklet that's only four sheets of copy paper and it's holding well enough. It's not as tight and secure as with higher page counts, but it's not bad and I expect it to improve when I find a clear cover to add.The widest part of the opening is about 5mm or 3/16", so depending on the type of paper, these should fit around 50 sheets at most. I tried one on 50 sheets to verify and although it was tough to get started, I was able to do it.Since these binders are 12" long, they stick farther beyond the ends of Letter size paper than really looks right, so I think they're better for A4 size paper. Also, although they are described as white, mine all look a bit grayish, like they are probably made of recycled material. That's fine for my purposes, but if you really need pure white for some reason, you may want to skip these.The biggest negative is pricing. The package contains only ten binder bars and no covers at a price where competitors offer thirty bars or a dozen that include covers. There is nothing particularly wrong with these, but I also see no obvious reason for the premium pricing.