Optimum® - ProSeries™ - STERILE Conical Centrifuge Tubes FreezeTech™ Temperature Indicator - Changes Color at 0°C • 20,000×g Max RCF Marked Directly on Tube • Hi-Viz™ Graduations, Including Maximum Freeze Line • Eco-Plastic Racks and/or Resealable Zip Bags • E-Beam Sterilized (SAL 10-6)