Nalgene MF75 Series Bottle Top Filter, Supor machV membrane, Fits 45mm Media Bottle Neck, 0.2 Micron, 90mm Membrane Diameter, 1000mL Capacity (Case of 12) Filter capacity: 1000ml Material: polystyrene housing with a Supor machV PES membrane Membrane diameter: 90mm; pore size: 0.2m Filter securely screws onto glass media bottles with 45mm neck sizes Features molded-in graduations and a side-arm with quick-disconnect tubing adapter; blue collar