The oxygen nipple nut adapter, also call a xmas or christmas tree adapter, is treaded on one end and tapered on the other. It is designed to screw on to the front of some oxygen concentrators to connect oxygen supply tubing. Oxygen supply tubing has universal fittings, so there is no need to worry if this is compatible with your tubing. If you currently have a humidifier bottle connected, you would remove the bottle, screw the nipple nut adapter, and attach an oxygen cannula or oxygen supply tubing. 

 Altra Service Professionals.

MPN: CT-OP