Novas Bio Snap-lock Microcentrifuge Tubes are designed to deliver maximum performance in a variety of applications. Molded from medical-grade virgin polypropylene, the Tubes are exceptionally clear and resistant to stretching and bulging when subjected to even demanding centrifugation. The Snap-lock Cap assures a tight seal, while remaining easy to flip open. The seal design ensures a sealed Cap during boiling even after repeated opening and closing. The flat Cap as well as the Tube feature a frosted, writable surface for easy sample identification. Graduation marks are molded in place for optimum accuracy. Ultra smooth tube bottoms deliver perfect clarity with no cuts or scratches. Tubes are capable of withstanding up to 18,000 x g, in fully supported rotors and are autoclavable.