Barely there — until you need oxygen on the go
At about 2.8 lb, the Inogen One G4 slips into a small bag and goes wherever you do — errands, travel, a day out. Buying it Certified Pre-Owned gets you a genuine Inogen G4 rebuilt with new critical components and tested by our technicians, at a fraction of the price of new.
Genuine Inogen device. FAA-approved for air travel and FDA-cleared. Prescription required. 1-Year Warranty by American Oxygen.Why the Inogen One G4
About 2.8 lb with a single battery. The G4 disappears on your shoulder — exactly why active users and frequent travelers pick it.
Our Certified Pre-Owned G4s get new sieve beds, a new lithium battery, new external accessories, and a compressor replaced or tested to spec — not a used-as-is unit.
FAA-approved for commercial flights, with single and double battery options so you can plan runtime around your day or your flight.
If a covered issue ever comes up, you're backed by our U.S. warranty and support team — no gamble on a private used sale.
Battery runtime by setting
| Battery | Setting | Runtime |
|---|---|---|
| Single (4-cell) | 1 | ~2.5–2.7 h |
| Single (4-cell) | 2 | ~1.5–2.0 h |
| Single (4-cell) | 3 | ~1.0–1.3 h |
| Double (8-cell) | 1 | ~4.8–5.0 h |
| Double (8-cell) | 2 | ~3.0–3.5 h |
| Double (8-cell) | 3 | ~1.8–2.3 h |
Per-setting runtimes are American Oxygen estimates; Inogen publishes only the setting-1 maximum. Actual battery life varies with breath rate, altitude and battery age.
Details
Technical specifications
| Flow type | Pulse dose only (no continuous flow) |
| Flow settings | 3 (settings 1–3) |
| Max oxygen output | 630 mL/min |
| Weight | 2.8 lb with single (4-cell) battery |
| Dimensions | 7.2 × 2.68 × 5.91 in with single battery (6.5 in tall without battery) |
| Battery options | 4-cell (single) or 8-cell (double) |
| Battery life | Up to ~2.7 h single / up to ~5 h double (setting 1) |
| Sound level | ~40 dBA (setting 2) |
| Connectivity | Inogen Connect Bluetooth app |
| Power | AC 100–240V · DC vehicle adapter |
| Air travel | FAA-approved · FDA-cleared |
| Warranty | 1-Year Warranty by American Oxygen |
| Condition | Certified Pre-Owned — new critical components, tested |
Warranty & condition
The Inogen One G4 Certified Pre-Owned is a genuine, ultra-compact pulse-dose portable oxygen concentrator with three flow settings (1–3) and up to 630 mL/min of oxygen. At about 2.8 lb with a single battery it's one of the smallest concentrators available, with Inogen Connect Bluetooth, and it's FAA-approved for air travel. Certified Pre-Owned means a previously used unit that American Oxygen inspected, rebuilt with new critical components, cleaned and tested to like-new performance, backed by a 1-Year Warranty by American Oxygen. Prescription required.
Frequently asked questions
What does “Certified Pre-Owned” mean for this G4?
How small and light is the G4?
How long does the battery last?
Can I fly with the Inogen One G4?
Single or double battery — which should I choose?
Do I need a prescription?
Not sure this is your setting? We'll help you choose.
Talk to a specialist — we'll confirm the right concentrator and flow for your prescription.
Call (786) 755-8063
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David –
The Inogen G4 is an excellent choice if you need the lowest oxygen flow. Super lightweight. Thanks!