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. Designed for use with 22mm tubing. Installation and replacement are quick and easy. The filter connects between the machine's air inlet or outlet and the hose. For best results, use to help maintain clean airflow for improved therapy performance. Pack of 6 filters. Latex-free. Each filter is individually sealed. Material: ABS Color: As shown Package Contents: 6 x Filters Note: Light and screen display differences may cause slight variation in color compared to the actual item. Measurement tolerance: +/- 1-3cm.