This combination brings together RIDGID AC840081 18V 8.0Ah MAX Output EXP Battery and 18V 4.0 Ah MAX Output Battery to create a complete solution. The RIDGID AC840081 18V 8.0Ah MAX Output EXP Battery delivers maximum power and the longest runtime for the most demanding work. The RIDGID 18V MAX Output EXP Batteries unleash extreme performance and are the best batteries in the RIDGID 18V system. Tabless cells create a more direct flow of energy to maximize power, runtime, and cell life while enabling faster charging. Advanced Intelligent Electronics communicate directly with the tool to optimize output and maximize battery performance during high demand use. ThermaGuard technology utilizes laser welded cell straps and upgraded heat sinks to help keep operating temperatures lower and maintain consistent output under heavy use. Built to withstand the toughest jobsite environments, this battery features a durable pack design for dependable use day after day. Quickly recharge the battery by pairing with the 18V Turbo Charger (AC96099 sold separately) to achieve a ready state 80% charge in 40 minutes. Work all day with RIDGID's most dependable, best performing battery. This RIDGID 18V 8.0Ah MAX Output EXP Battery is 100% compatible with all RIDGID 18V tools. This kit includes RIDGID AC840081 18V 8.0Ah MAX Output EXP Battery and 18V 4.0 Ah MAX Output Battery.