As the most powerful AP System battery, the AP 500 S allows professionals to tackle larger jobs with more power than other batteries in the AP System. Built with STIHL's exclusive power laminate cell technology, the AP 500 S gives you up to a 2, 500-cycle life. The AP 500 S offers an improved power-to-weight ratio and features 40% more power output and 20% more capacity than the AP 300 S. The AP 500 S is compatible with most tools in the AP System, allowing you to easily switch from one job to another. Additionally, this top-of-the-line professional battery comes with an exclusive battery management system that allows the motor's electronic control system to compensate for the reduction in voltage by increasing amperage, resulting in consistent power over the entire running time. | STIHL AP 500 S Battery