Thermo scientific screw cap microtubes Screw cap with 0-ring Violet Thermo scientific Thermo Scientific Screw Cap Micro Tube caps with O-ring are designed to create a secure seal with the Thermo Scientific micro tube providing Pure Protection for sample preparation, transfer, and storage applications. Non-Sterile is free of Rnase/Dnase, DNA, Pyrogen & Endotoxin Sterile E-Beam is free of Rnase/Dnase, DNA, Pyrogen, Endotoxin, ATP, PCR Inhibitor 100% virgin polypropylene resin specifically selected for high clarity and biological applications O-ring design, thickness, and material selection have been optimized to provide protective features for maximum sealing ability, biologic interaction, and temperature capability. The black-colored O-ring is made from EPDM Knurled caps improve grip when opening and closing tube Frosted cap writing pad for easy product marking and identification Color caps offered in multiple color options ideal for separating, coding, and tracking samples. Amber-colored caps ideal for UV protection of 1.22% transmittance between 220 and 500nm Tethered caps remain attached to the sample tube but can rotate completely for convenience the tethered screw cap is the solution when it is important to maintain the same cap with the same tube. Non-tethered caps available RCF range from 18,000 to 25,000 x g Temperature Range -80 C to +95 C. Short term storage in -80 C, -20 C, dry ice, and wet ice. Short term storage in vapor phase LN2 and suitable for a quick dip flash freeze in LN2 Torque Manual/Hand Torque: Standard: 0.125 lbs.in to 2.5 lbs.in; Metric: 1.412 Ncm to 28.24 Ncm. Torque Automated/Robotic Torque Standard: 1.312 lbsf.in to 2.5 lbsf.in; Metric: 14.83 Ncm to 28.24 Ncm