CO2 back-up bottle from Power Tank. It's great to have a spare tank full and ready to go when you need it. You can store it in the garage between trips, in the trailer at base camp, or bring it along in the rig on long runs. Being able to rotate your bottles will save you from "gas anxiety." Includes a Sherwood nickel plated valve. 

We recommend adding a tank boot and a Power Grip Guard handle so all you need to do is swap the regulator over when you need to switch.