Nalgene Rapid-Flow Sterile Disposable Bottle Top Filters. Perform sterile filtration of cell culture media, serum, additives and buffers with Nalgene Rapid-Flow Sterile Disposable Bottle Top Filters with PES Membranes. Features fast flow rates, a high throughput for increased filtration efficiency and exclusive Rapid-Flow support plate design. Securely screw onto media bottles with 45-mm neck sizes. Allow vacuum filtration of liquid directly into sterile bottles. Certified. Sterile. Graduated. Upper 500ml. Membrane PES. Pore Size 0.45 µm. Diameter 75mm. Pack Qty 12. Fits Neck 45mm. Type Bottle Top.