These Corning PCR tubes are made of thin wall polypropylene and are designed for precise fit in heat blocks to optimize heat transfer. Nonsterile and certified DNase- and RNase-free. Autoclavable at 121°C and will withstand centrifugation to 10,000 x g. The 0.2mL tube is available with attached dome or attached flat cap. 0.5mL tube has an attached flat cap. Thermowell® GOLD 0.2mL PCR tubes, in clear or assorted colors, are available with flat caps for easy piercing and marking or with domed caps for efficient heat transfer.