TwistLock Microcentrifuge Tubes from Light Labs are ideal for long term use in a variety of situations. Manufactured to the most rigid standards, these tubes can be used in extremes of termperature: from vapor phase liquid nitrogen to boiling applications. The cap and O-Ring are designed to be the perfect complement to the TwistLock Microcentrifgue Tubes, thus ensuring a perfect seal. The naturally low binding properties of the polypropylene, the leak-free seal, and certified freedom from RNase, DNase, and DNA, makes these tubes an ideal long-term storage solution. The tubes are rated at 20,000 x g and are suitable for use in molecular biology applications. TwistLock Microcentrifuge Tubes fit most standard rotors.