This is an oxygen cylinder backpack carrier that comes in 2 sizes: one fitting M6, C/M9 and smaller cylinders, and the other fitting D sized cylinders. Also, you can convert this oxygen carrier from a backpack to a shoulder bag to better suit what’s comfortable for you. This AirLift oxygen carrier also has a fully adjustable waist belt, plus its backpack straps have an ergonomic design for more comfort. And for even more comfort, the cylinder pouch is heavily padded so it won’t create uncomfortable pressure points while you wear it on you back. This oxygen backpack also has a convenient large accessory pocket to carry extra cannulas, tubing connectors, or other accessories you may need. The backpack oxygen carrier is well ventilated for unsurpassed safety, and made of non-flammable, non-abrasive material. The carrier is machine washable (hang dry), and comes in navy blue.