The inline filter is suitable for CPAP devices. It is used in combination with the machine's built-in inlet filter to deliver very clean air. The outer diameter of the connector end: 25mm. The inner diameter of the female connector end: 22 mm. Suitable for 22 mm pipe making machine. Installation and replacement are quick and easy. The filter is connected between the air or outlet of the machine and the CPAP hose. Best Results: Keep the air inhaled by the CPAP machine clean for the best therapeutic effect. A set of 6 filters. Does not contain latex. Each filter is individually sterilized and sealed. Material:ABS colour:As Shown Package Contents: 6 x filters Only the above package content, other products are not included. Note: Light shooting 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.