These Polypropylene / Polystyrene tubes are generally used in RIA, Coagulation & Bacteriology. The Polypropylene tubes are clear and can withstand 3000 RCF during Centrifugation while the transparent Polystyrene tubes can withstand 1400 RCF. The PP tubes can accept common acids, alkalies and solvents at room temperature while the PS tubes can accept mild bases, weak acids but not organic solvents.