Oxygen concentrators are used along with CPAP therapy to help elevate blood-oxygen concentration. Their use allows more oxygen to enter the lungs and helps you feel more rested upon waking. They work by concentrating atmospheric oxygen and delivering it to your mask via an oxygen supply tube which attaches to your concentrator and mask. No additional oxygen canister is needed, making this therapy perfectly safe for at home use. Be sure to talk to your doctor about the use of an oxygen concentrator and keep him or her informed during therapy.