1. To insert the optional HumidX / HumidX Plus, for N20 or AirFit P10 for AirMini users, open the connector by gently twisting. 2. Grip the HumidX / HumidX Plus at the edges, with blue / grey side facing down towards the tube, and place it inside. 3. Close the connector by twisting its ends back together until they lock into place. 4. HumidX and HumidX Plus must be discarded and replaced within 30 days after opening the HumidX / HumidX Plus packaging.