Large connector hose that connects/transports O2 from bag to Mega-Flow mask plus the plug/cork to stop O2 leakage when system not in use.
The bag comes with two hoses to fit the dual mega flow mask. To extend them or allow for two people using the bag at the same time, you will need TWO hoses per mask. While purchasing, add 2 hoses to your cart. This also includes 1 copper connector for every 10 feet hose.