Saf-T-Seal screw cap microcentrifuge tubes are strong enough to withstand centrifugation up to 20,000 x g. Suitable for use in vapor-phase liquid nitrogen storage, -80°C freezers, boiling, and autoclaving. Deep external threads protect against sample loss and seal failure. An interior U channel in the lid keeps the ethylene propylene rubber (EPR) "O"-ring in place as the cap is tightened. Certified free of detectable RNase, DNase, DNA, and pyrogens. Sterilized tubes packaged in 10 sealed bags of 50 tubes and caps (natural color only).

Tubes are assembled with caps in place before packaging.