Microcentrifuge tubes are small plastic tubes commonly used in laboratories for various applications such as sample storage, centrifugation, and PCR (polymerase chain reaction). These tubes typically have a capacity ranging from 0.2 mL to 2.0 mL. They are made from materials such as polypropylene or polyethylene, which are chemically inert and resistant to a wide range of chemicals and temperatures commonly used in laboratory procedures.