You can use batteries or electricity — it's your choice. But for best results we do recommend using the included AC adapter, especially in the early stages of training when the dog will be barking more. Battery life will vary depending on the weather, the quality of the batteries used, as well as how often the unit is being activated. If you need to use batteries, rechargeables are a great option to save money. We also offer a new Solar Panel add-on! Note: Please do not use aftermarket AC adapters ( those not purchased from Good Life ) as this will void your product warranty.