Build your own tool kit with the Makita 40V max XGT Battery and Charger Starter Pack (4.0Ah) (BL4040DC1). Makita offers over 125 XGT equipment and tools that utilize 40V Lithium-ion batteries, most available as "bare tools" (tool only, no batteries or charger included). Pick up the Makita Battery and Rapid Optimum Charger Starter Pack, then purchase the 40V "bare tools" you need to get the job done. It's an ideal way to start building a Makita XGT Cordless System.XGT batteries feature an advanced design impact-resistant outer case and shock-absorbing inner-liner engineered to protect the battery in harsh job site environments. The XGT Rapid Charger's built-in chip thoroughly communicates during the charging process to control current, voltage, and temperature for more efficient charging. The digital communication within XGT actively monitors and protects against overload, over-discharge and overheating.XGT is a system of equipment, tools, batteries, and chargers utilizing 40v max lithium-ion batteries. XGT is engineered to deliver high power to take on high-demand applications, allowing users to completely transition to a cordless job site. XGT is equipped with advanced brushless motor engineering, intelligent digital communication, and superior durability features to outpower, outsmart and outlast the rest.