The Inogen One G2 Portable Rental it a smaller and lighter concentrator that has a longer lasting battery. It's so small and portable that is can be hand held and has a battery life that can last up to 3 and a half hours on a setting of 2 with the 12 cell battery. It is a pulse dose machine that delivers pulse dose oxygen on setting from 1 to 5. It is a great solution for a oxygen concentrator rental. The Inogen One G2 is your oxygen rental solution, for oxygen home and away.