15 lb CO2 Spare Bottle PowdercoatedCO2 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. All 10 lb, and 15 lb spare bottles come with a free Tank Boot ($24. 95 value). We recommend adding a Power Grip Guard