Barely used Phillips Respironics Simply Go portable oxygen. Private party sale. Works with batteries (4 extra), plugged into household outlet or plugged into vehicle accessory port. Extremely quiet running. Also has optional wheeling cart, shoulder strap and case, extra charging cord and extra car cord. Delivers continuous flow up to 2 liters and pulse flow up to 6 liters. Willing to drive to meet in a public central location for a serious buyer. Asking $1250. This is way less than half the original cost, used only as a back up, likely about 15 hours running time.