Place blocks on ice, dry ice, liquid nitrogen, or in a water bath. These anodized aluminum blocks can keep samples at or near 1°C for up to 8 hours in properly packed ice, or for 3 to 7 hours in dry ice. Choose the blocks that meet your application needs — configurations are available for 1.5-/2.0-mL microcentrifuge tubes and cryogenic vials, 0.5-mL tubes, and 96-well or 364-well plates.