If your oxygen concentrator does not have a threaded attachment on it for a humidifier bottle, you will need this Oxygen Humidifier Adapter to attach a Humidifier Bottle to your concentrator.

This Humidifier Adapter has a threaded nut on one end that attaches to standard oxygen humidifier bottles. The other end of the adapter is a plain tube that slides over the nipple port on the concentrator. It offers a quick and easy solution to adapt humidifier bottles to oxygen concentrators.