Versatile polypropylene rack, suitable for freezer storage. Reversible format accommodating 0.5ml microcentrifuge tubes on one side and 1.5 to 2ml microcentrifuge tubes, cryovials or sample tubes up to 12mm o.d. on the reverse side. The larger apertures are 12mm o.d. to a depth of 10mm where they narrow to 10.8mm for a further depth of 15mm. All apertures are widely spaced apart to accommodate screw cap vials and for ease of use when inserting or removing tubes. Both sides of the rack have moulded-in alphanumeric references. Autoclavable at 121°C for 15 minutes.