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 & solvents at room temperature while the PS tubes can accept mild bases, weak acids but not organic solvents.