In line filter cleans the air leaving a CPAP or BiPAP machine. It is used in conjunction with the machine's built-in inlet filters to provide very . Male Connector End Outer Diameter: 15mm. Female Connector End Interior Diameter: 22mm. Fits 22 mm tubing machine. Quick & Simple to Install and Replace. The filter attaches between the machine's air or outlet and the CPAP hose. Efficiency: 99.99+%. Latex Free. Each filter is individually and sealed.<br><br>Colour: transparent Material: plastic<br><br>Package Contents: 12 * Filters<br><br>Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.