The inline filter is compatible with CPAP devices and works in combination with the machine's built-in inlet filter to help deliver clean air. Outer diameter of the connector end: 25mm. Inner diameter of the female connector end: 22mm. Compatible with 22mm tubing. Installation and replacement are quick and easy. The filter connects between the air outlet of the machine and the CPAP hose. For best results, use to help maintain clean airflow for improved therapeutic performance. Set of 6 filters. Latex-free. Each filter is individually sterilized and sealed. Material: ABS Color: As shown Package Contents: 6 x Filters Note: Light shooting and different displays may cause slight color variations between the image and the actual item. Measurement may vary by +/- 1-3cm.