Nalgene 3120 Polypropylene Copolymer (PPCO) Centrifuge Bottles with Caps are a great choice for biopharmaceutical aseptic fluid transfer or sampling applications, Molded of transparent polypropylene copolymer. Ideal for large-volume cell harvesting, pelleting and protein purification, these translucent bottles are autoclavable and have excellent mechanical strength properties. Sealing cap Cat. No. DS3131-0038 is available for 250mL size and Cat. No. DS3132-0063 is available for 1000mL capacity bottles.