WE are Genuine Manufacturers of this product and we manufacture this at our manufacturing facility in New Delhi B&V FILTER 22 mm ID x 15 mm ID22 mm OD Bacterial efficiency 99.99+%; viral efficiency 99.99+% Dead space is 45 mL Flow resistance approximately 1.5 cm H20 at 60 lpm FOR OEM AND PRIVATE LABEL PACKING FEEL FREE TO CALL..............