The Festool Energy set is the ideal addition for Festool users. Two Airsteam Bluetooth batteries supplied in a Systainer³, with space for a total of four battery packs. The DUO charger is extremely practical onsite, charging two battery packs at the same time from one power socket. The 4.0Ah battery packs are compact and lightweight, yet powerful enough for use with Festool drills, saws, multitools and extractors. The 5.2Ah battery packs are powerful all-rounders for all applications and compatible with almost all Festool battery products. Especially suitable for applications with a focus on power and endurance such as grinding, cutting and sawing systems, and extensive dust extraction. Note: these batteries are not compatible with Festool ETSC, DTSC and RTSC sanders. Features Dust extraction starts automatically: The Bluetooth battery packs automatically start the connected mobile dust extractor when the tool is switched on With smart extensions: The Festool WorkApp enables clever additional functions in combination with the Bluetooth function of the battery pack, such as the detailed display of the charging status and further operating data such as temperature or charging cycles. Airstream Technology rapidly charges compatible batteries in 40-70min, cooling the battery to significantly increase capacity and provide faster charging. LED charge status indicator directly on the battery pack Software updates are also possible: Install the newest version to work with the latest tool functions at all times. Safely stored and mobile: Stowed in Systainer³ with sufficient space for a total of four battery packs and the DUO rapid charger. Better with a system: The Systainer³ is compatible with and can be attached to all previous Systainer generations, mobile dust extractors and many more system accessories Includes 2 x Airstream Bluetooth battery packs DUO rapid charger Systainer³