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 is 25mm. The inner diameter of the female connector end is 22mm. Compatible with 22mm tubing. Installation and replacement are quick and easy. The filter is connected between the air outlet of the machine and the CPAP hose. For best results, use to help maintain clean air intake for optimal 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: Lighting and monitor settings may cause slight color variations between the image and the actual item. Measurement may vary by +/- 1-3cm.