Usage Tips:Material: These filters are made of ultra-fine fiber cotton which can effectively filter fine particles, dust,and pollen. Bisphenol-A free, safe and reliable. Thickened Design: Other filters are only about 1mm thick, but this filters are about 3mm thick, the filter can filter fine particles, , viruses and other harmful substances in the air, improving the filtration effect of the respirator. Better Compatibility: Each filter measures 2 x 0.9Inch. The size of filters are better for Airsense 11 machines, no unnecessary gaps, better filtration effect. Improve The Air Freshness: Each filter is designed to block more fine particles and large particulate matter, the air output from the ventilator is cleaner and fresher, which helps to improve the air quality and protect the health of patients and Improves quality of patient's sleep. Extend The Life of The Machine: for Airsense 11 filters can block the dust, impurities and other substances into the ventilator, effectively reduce the loss of the ventilator internal, reduce the cost of cleaning and maintenance of the ventilator internal, extend the life of the Machines. Colour:White Material:cotton Package Contents: 30 * Filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.