HACENOR 3L Continous Flow 90% High Purity Portable Oxygen Concentrator 24/7 Continuously Work With 4.5 Hours Battery 1001BX Type:Oxygen Concentrator(With Built-in Battery)+1PC External Battery Large capacity lithium battery:Not affected

Large capacity lithium battery:Not affected by power failure

Strap the backpack directly behind the seat

Weight Machine Weight About 4

Nice design

HACENOR 3L Continous Flow 90% High Purity Portable Oxygen Concentrator 24/7 Continuously Work With 4.5 Hours Battery 1001BX Type:Oxygen Concentrator(With Built-in Battery)+1PC External Battery Large capacity lithium battery:Not affectedSpecification: Model Number 1001BX Oxygen Flow Mode Continuous Flow Oxygen Flow 1L to 3L Oxygen Purity 90%3% at 1L,63% at 2L,38% at 3L Weight Machine Weight About 3KG(6. 6lbs) Noise 45 dBA At Any Setting Dimension 225mmx120mmx177mm Charge Time 4 to 5 Hours Per Battery From Fully Discharging Battery Duration Internal battery can be used 2 hours after fully charged. External battery can be used 2. 5 hours after fully charged.