While some portable oxygen concentrators are very small – think around 5 pounds – others are larger in a mid-sized range – around 10 pounds – and others are around 20 lbs. This variation in size depends mostly on how much oxygen its capable of delivering, in LPM (liters per minute) for continuous flow oxygen, and ml per minute, such as the pulse dose settings. Some portable oxygen concentrators have both
continuous flow and
pulse dose settings, such as the SeQual Eclipse 5, while others only deliver pulse dose oxygen, such as the Respironics EverGo.
Some of the very small concentrators do not have a battery that can be taken out and put back in, but you can supplement their battery life with a battery pack, which you can wear like a belt, such as the case with the small AirSep portable models, the AirSep Freestyle, Freestyle 5 and the AirSep Focus.