The inline filter is suitable for CPAP devices. It is used in combination with the machine's inlet filter to deliver 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 hose. Best Results: Helps maintain clean air delivery for optimal CPAP therapy performance. This package includes a set of 6 filters. Each filter is individually sealed. Material: ABS Color: As shown in image Package Contents: 6 x Filters Note: Light and display settings may cause slight color variations compared to the actual product. Measurement allowance is +/- 1-3cm.