Owgels Classic 603 

This transportable oxygen concentrator is the median of the types of oxygen concentrator wherein it is 3 liters. Again, it employs the dual-function technology. 

However, instead of the nebulizer function, it has the anion function which helps eliminate harmful air particles. The transportable oxygen concentrator is a very handy and reliable oxygen concentrator also with the state-of-the-art dual-function technology employed by its more heavy-duty counterpart.