The inline filter is compatible with CPAP devices and works in combination with the machine's built-in inlet filter to help deliver cleaner 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 air inlet or outlet of the machine and the tubing. For best results, maintain clean air intake for optimal CPAP therapy performance. Package includes 6 filters. Latex-free. Each filter is individually sealed. Material: ABS Color: As shown Package Contents: 6 x Filters Note: Light and display settings may cause slight color variations between the image and the actual item. Measurement allowance is +/- 1-3cm.