Enter the 40V System with the RYOBI 40V HP Brushless 21" Self-Propelled Lawn Mower. With 40V HP Technology delivers more power than a 163cc gas mower, making this mower a true gas replacement. Dual active battery ports and two included 40V 6Ah lithium batteries give you up to 70 minutes of runtime for tackling up to 3/4 acre with ease. 40V HP technology combines a brushless motor, advanced electronics, and lithium batteries that automatically react to mowing conditions by increasing the blade speed to eliminate bogging down and power through the toughest cut. The variable speed self-propelled drive system ensures an effortless, efficient mowing experience. Best of all, it is part of the RYOBI 40V system where any 40V battery works with any 40V product. This self-propelled mower is backed by the RYOBI 5-Year Manufacturer's Tool Warranty, 3-Year Manufacturer’s Battery Warranty, and includes the RY401014 40V HP Brushless 21" Self-Propelled Mower, (2) OP40605 40V 6Ah Lithium Batteries, OP406 40V Rapid Charger, Grass Catcher Bag, Start Key, Mulch Plug, Side Discharge Chute, and Operator's Manuals.