CryoKing 3.75 Inch 81-well Cryo Boxes, Lab Freezer Boxes with Connected Lid, ID-Color Cardboard Freezer Boxes with Straight Grid Divider, 5Pcs

Made of durable cardboard with a waterproof coating and polypropylene dividers Connected lid design ensures that lids are never misplaced or mixed up Alphanumeric labeling featured on the lid, bottom and four sides enables quick and easy identification of samples Holds 5.0ml microtubes and cryogenic vials Working temperature: stable from -86°C to 121°C, Suitable for liquid nitrogen freezing(vapor phase) (after adding vent holes, and using cardboard dividers)