Durable polypropylene containers hold five standard (3 x 1 or 75 mm x 25 mm) slides. The inside wall has slotted channels to keep slides separated and for easier removal. Choose from end-opening or side-opening versions, both close securely to keep slides safe. The side-opening mailer measures 81 mm x 19 mm x 31 mm; the end-opening mailer is 88 mm x 24 mm x 43 mm. Comes in packs of 25.