Inogen One G4 Oxygen Concentrator // One year old.. With a 2 year transferrable warranty Search for: Advanced Search Place Ad Browse Ads Search Ads Inogen One G4 Oxygen Concentrator // One year old.. With a 2 year transferrable warranty Contact Information Contact HelenHank Phone: 9414670730 Price: $ 1,800.00 More Information Like new. Includes case New $2,300 This Ad has been viewed 0 times.