Thermo Scientific™ Nalgene Polypropylene Floating Microtube Racks are especially used in genetic cloning, microbiology and immunology labs. Offers excellent temperature resistance from -70° to +100°C (-94° to +212°F). Thaw, cool and incubate samples at elevated or reduced temperatures. 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. Square- and round-style racks for incubating 0.5 to 2.0mL microcentrifuge tubes at elevated or reduced temperatures in water or ice baths Round-style racks fit conveniently inside 400 or 1000mL beakers Racks will float with a full load of filled tubes Tubes are supported below the lip while conical ends are immersed in water On benchtop, rack legs prevent bottom of tubes from touching bench surface Thaw, cool and incubate samples at elevated or reduced temperatures—tolerates a wide temperature range Tubes are securely supported in the rack below the lip Each hole has molded-in letters and numbers for easy sample identification Racks are NOT autoclavable