Bosch 1600Z00038 18v 4.0Ah Lithium-ion CoolPack Battery.
Featuring electronic coding for tools & chargers, high power contacts with silver coating, capacity indicator with 3 LEDs, red CoolPack housing constructed of heat conductive material, in-built temperature sensor, large ergonomic release button for ease of use, robust housing & slide-in interface.
Efficient Bosch cooling technology in & around the battery prevents heat damage, gives up to 65% longer run-time & up to 100% longer lifetime. 4.0Ah CoolPack cells have finer 'windings' than 3.0Ah allowing more power density in the same pack size with less electrical resistance, making it more efficient.
This means less frequent battery charges & 4.0Ah batteries are fully charged in just 45 minutes.