This is a set of five B5 graph paper notebooks. I purchased these along with other notebooks, but I don't use graph paper, so I'm offering them to someone who will. I counted the sheets, and two notebooks have 40 sheets each, so I believe they are unused. The remaining three notebooks appear to have had one or a few sheets used, so they are less full. I don't notice any yellowing, but please understand that these have been stored at home by a non-professional. Thank you.