Microscope slide storage boxes, mailers, etc. Although originally designed to mail slides safely, many people use them to store individual slides as they provide plenty of room to attach a label giving information on the specimen.
Photo shows it in both open and closed positions.
Snaps closed and seals tight. Package of 12. Tight fitting cover and clean white appearance. There is plenty of room on the inside of the cover to attach a summary. Nicely finished wood box is hinged and has latches to keep it closed.