These microcentrifuge tubes incorporate superior clarity with phenomenal strength. Glass-like clarity allows easy viewing for sample and pellets. Ideal for high-speed centrifugation, proprietary homopolymer polypropylene tubes are rated up to 25,000 x g. These microcentrifuge tubes have a positive seal design that allows repeated cap closures and will not pop during boiling or freezing. All tubes feature external graduation marks and frosted writing surfaces. Temperature rating from -80C to +121C. Fits all standard rotors. Autoclavable.