MTC Bio’s 5mL MacroTube® Cardboard Freezer Boxes are made of recyclable material, with a liquid-resistant outer coating. They are shipped fully assembled and are available in a 5×5 version that holds 25 x 5mL Snap-Cap tubes or a 6×6 version that holds 36 X 5mL Screw-Cap tubes. Each box has liquid nitrogen drainage slots and numbered grid markings in almost every conceivable location (top, bottom, sides, etc.).