Cardboard freezer boxes for 5mL MacroTubes. MTC Bio's new boxes are designed to fit Screw-cap (36 tubes) and Snap-cap (25 tubes) type 5mL centrifuge tubes. The 17mm round holes keep tubes upright and far more secure than traditional square divider grids. Alpha-numeric indexing is provided in every imaginable place, including outside, inside, on the lid, and adjacent to each circular grid hole. And, the lid s permanently attached (no more mix-ups). Both box types have drain slots in the bottom and a white marking area on the front of the lid. Dimensions: 5.25 x 5.25 x 3inch(133 x 133 x 75mm).