Easy to use and replace. Replacement Exhalation Vent Diffuser for AirFit N30i and P30i ,with Multi-hole Vent Filter for N30i and P30i. Suitable for three size: Small, Medium, Large, Small Wide and Wide. We recommend you replace it every 2 weeks. QuietAir vent breaks up exhaled air for a quiet experience that is less disruptive to the bed partner. If you have any issues, please let us know and we will help solve it immediately.