Thaw, cool and incubate samples at elevated or reduced temperatures with Thermo Scientific™ Nalgene™ Polypropylene Floating Microtube Racks. Especially useful in genetic cloning, microbiology and immunology labs, these racks offer excellent temperature resistance from −70° to +100°C (−94° to +212°F). Tubes are supported in the rack below the lip. Square or round racks have molded-in letters and numbers at each hole for easy sample identification. Product Overview