These 50 ml centrifuge tubes are also useful for collecting and transporting biological specimens. Leakproof characteristics are assured by a flat top plastic screw cap with an inner sealing lip. Tubes are made of translucent polypropylene or optically clear polystyrene with molded graduations from 2.5 to 50 ml. Polypropylene tubes can be autoclaved and will resist temperatures up to 120°C, and also acids, solvents and alkalies at room temperature. They withstand centrifugation speeds of 3000 rcf or 5000 rpm. Polystyrene tubes can tolerate aqueous solutions of mild bases or weak acids, but not organic solvents, aromatic or chlorinated hydrocarbons, and they cannot be autoclaved. They withstand centrifugation speeds up to 1000 rcf or 1500 rpm.
Tubes are available in bags or in break-away polyfoam racks for better protection during transport, storage and for convenient laboratory use. Racks can contain up to 25 tubes. Tube contents are visible from top to bottom since they are provided with viewing slots. They are supplied sterile with green caps or non sterile with yellow caps.