This external 80 watt power supply meets the requirements of only PR System One REMStar 60 Series Machines and is NOT for use with any other machines in the Philips Respironics line of products.
To determine the series number of your System One machine, look at the bottom of the machine. Find the word “REF” enclosed in a rectangle, and read the number next to the word REF. If you see “50” in the number next to the word REF, it is a System One 50 Series. If you see “60” in the number next to the word REF, it is a System One 60 Series.