●Pure Material: These conical centrifuge tubes are made of high purity Polypropylene(PP) material which gives longer and durable usage. It can be used from -80°C / -112°F to 120°C / 248°F ●Leak-proof: These tight leak-proof screw caps prevent leaking and are safe for each working second ●Clear Scale: No more hard time reading with a clear & accurate graduated scale to ±2% ●Markable Area: There is a writing area for easy distinction ●Wide Applications: These lab tubes can be used in the field of biochemistry and molecular biology for seperation & preparation