The BP 18 Li 5,2 AS battery packs have an integrated cooling duct that reduces the cooling time and shortens the entire charging process by up to 65%. In other words: your tool is ready to use sooner – for interruption-free work, even for high-energy applications such as sawing. The Festool 5.2 Ah li-ion battery cells are resistant to high currents and retain energy reserves even when operating at full power. The new AIRSTREAM battery packs replace the previous 5.2 Ah battery packs and are compatible with the Festool 18v Li-ion power tools range.