The Inogen One G4 double cell Battery, Model BA 408, is a high-quality lithium-ion battery with a voltage of 14.4V. Double cell battery provides reliable and long-lasting power for your devices. The Inogen brand is known for its superior quality and performance, making this battery a great choice for those in need of a dependable power source. This battery has been used, but still keeps a charge which is shown by the green light visible in the picture.