5055 Microcentrifuge Tube Boxes for 64 and 81 tubes Materials:Polycarbonate Provide storage of microcentrifuge tubes from -150癈 to +121癈 (not for use in liquid-phase liquid nitrogen). Transparent lid has printed grid for inventory purposes, permits viewing of contents, and is keyed in one position to prevent misalignment. Lid accepts writing with marker for box and tube identification. Autoclavable.