A 12-cell Lithium Ion battery can provide up to 4 hours of pulse flow dependent upon setting and breath rate. Having multiple batteries extends your time unplugged from the wall and gives you the opportunity to be away from home doing the things you love.
A unique feature of the Zen-O portable concentrator is the ability to utilize (2) batteries in the machine at the same time - doubling your battery duration.
If you're running low on power, it is easy to swap them with fully charged batteries to keep you on the go and living your active lifestyle.
Whether traveling across town, or across the country, having extra batteries is always a good idea.