Features: 100% brand new and high quality Clean air: These filters will actively clean the air and work in conjunction with machines with built-in filters to provide particularly clean air throughout the night and help prevent viruses. Essential for allergy sufferers: It is an excellent choice for sleep therapy users who are prone to get sick or allergic. Maintain strong airflow: Low airflow resistance means that users can maintain strong airflow from CPAP/BIPAP machines. Simple installation: just connect the filter between the air outlet of the machine and the standard CPAP pipe. Disposable filter: The filter lasts for an average of 4-6 weeks and then needs to be replaced, but your filter may last longer or shorter depending on the environmental conditions. As soon as the white filter materials start to get dirty, they should be replaced. Package Includes: 1x CPAP Filter Specifications: Material: Environmental Protection Material Hose Connection ID: Approx. 15mm/0.6inch Hose Connection OD: Approx. 22mm/0.9inch Machine Connection ID: Approx. 13mm/05inch Machine Connection OD: Approx. 25mm/1inch note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.