Polypropylene 81 or 100 cell 2" boxes hold most popular cryo and cold storage vials and fit into standard freezer racks. These boxes offer a convenient and cost effective alternative to polycarbonate boxes for storage of samples. Boxes have clear lids with locator grid to facilitate sample identification. Polypropylene boxes are designed to withstand temperature down to -80?. Storage of polypropylene boxes in liquid nitrogen is not recommended. Boxes have drain holes for venting and safety. Keyed lid prevents misalignment of grid.