This Oxygen Gear Bag's wide zippered pocket holds your C, D, Jumbo D, or E tank in addition to your respiratory treatment gear, allowing for easy access to the cylinder without having to remove it from the bag or even open the main compartment. For keeping O2 Supplies organized, it has a large main compartment, two large full-length gusseted side pockets, one easy-access end pocket, two zippered pockets.