The First Strike Dual Valve C02 Fill Station is great for filling your own co2 tanks. The dual valve fill station allows you to fill with one valve and dump the excess CO2 with the bleed valve. The two valves will save you from turning your tank on and off every time. A bulk supply tank is needed along with a scale to aid in filling. Bulk co2 tanks can be rented from local welding supply stores in your area usually.