3L Portable Battery Operated Oxygen Concentrators Machine products this means that the concentration

this means that the concentration of oxygen will be about 90% and there will be a 3% margin

and the state of printing mode

3)Oxygen Concentrator 49*49*63cm

Ramp Item: 0-60min adjustable 1min/Step

3L Portable Battery Operated Oxygen Concentrators Machine products this means that the concentrationPortable Oxygen Machine Features: Multi purpose: Awesome for home, car, travel, work, Including battery. Charge 4 hours, Work Time for 2. 5 hours. If need much more time, pls click HERE Low noise: less than 45dB, night use will not affect sleep, It works with or without water, no need to refill at night. It is a good backup for your home OC, 30% purity oxygens not adjustable. Not for medical use, couldn't work 24 7 Portable and light: Size: 9*4. 3*6.