18V combo kit with DCD999, DCF850, 2x Powerstack batteries (1x 1.7Ah and 1x 5Ah). Powerstack batteries offer several advantages over conventional cylindrical batteries at the same voltage level and comparable capacity: Efficient power flow due to lower internal resistance leads to significantly higher power output of the machine in certain applications. Noticeably longer runtime per battery charge. Large flat cells allow for better heat dissipation, increasing the number of charge cycles and thus the lifespan. An optimized fan system effectively cools the angle grinder and electronics during use, extending their lifespan. The electronic clutch automatically shuts off the device in case of blockage, protecting both the user and the machine.