New 4.0 Ah Lithium Ion CoolPack batteries have efficient Bosch cooling technology in and around the battery that prevents heat damage, gives up to 65% longer run-time and up to 100% longer lifetime.4.0 Ah CoolPack cells have finer 'windings' than 3.0 Ah, allowing more power density ('fuel' Ah) in same pack size and less electrical resistance (so more fuel efficient).That means less frequent battery changes; and 4.0 Ah batteries are fully charged in just 45 minutes (charger AL1860CV)!Features:- Electronic coding: for tools chargers- High power contacts: with silver coating- Capacity indicator: with 3 LEDs- Red COOLPACK: housing made of heat conductive material- In-built temperature sensor- High quality Li-Ion cells with highest capacity- Robust housing- Robust slide interface- Large and ergonomic release buttonCompatible with 18v Bosch Blue Professional cordless power tools with slide-on battery function