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 is placed between the machine's air inlet or outlet and the tubing. For best results, use to maintain clean air intake for improved therapeutic performance. Pack of 6 filters. Latex-free. Each filter is individually sealed. Material: ABS. Color: As shown. Package Contents: 6 x Filters. Note: Only the items listed above are included. Light and display settings may cause slight color variations between the image and the actual product. Measurement error allowed is +/- 1-3cm.