Release oxygen only when you inhale, extending the cylinder's life by 3–5 times, though they are more expensive. Top Brands and Alternatives What to Know about OTC Oxygen: Should You Use It?

Provide continuous flow; simpler and cheaper but consume oxygen faster.

Stationary units for continuous home support; these are heavy and often require a cart for movement. Delivery Mechanism:

The "E" cylinder is a standard for home use and can be mounted on a wheelchair; it balances capacity with manageable size.

Preferred for portability; lightweight and corrosion-resistant.