Small, lightweight, and long-lasting, encourages an active lifestyle for long-term oxygen therapy patients. No tubes, heavy canisters or batteries are required. The system is also extremely economical. Its pneumatic oxygen conserving device gives it a conservation ratio over continuous flow oxygen of approximately 4:1. This provides up to 10 hours of use at a setting of 2. The portable unit can be refilled in about 40 seconds from the home reservoir, which typically lasts four to six weeks between refills.