As the most powerful AP battery, the AP 500 S battery allows professionals to tackle larger jobs with more power than other batteries in the AP System. Built with STIHL exclusive power laminate cell technology, giving users up to a 2,500 cycle life. The AP 500 S features 40% more power output and 20% more capacity than the previous model and the best power-to-weight ratio in the STIHL AP System. The AP 500 S delivers maximum power while reducing user fatigue. It is compatible with most tools in the AP System, making it easy to switch from one job to another. Additionally, this top-of-the-line professional battery offers STIHL SMART Power, allowing the motor's electronic control system to compensate for the reduction in voltage by increasing amperage, resulting in consistent power over entire running time.