Looking for more power and longer runtime out of your HART 20V tools? Then this 20V 4.0Ah Battery 2-Pack is for you. Battery provides 4X the runtime* and features an on-board fuel gauge so you always know how much charge you ve got left. Plus it s compatible with all HART 20V power tools. 20V 3 AMP Fast Charger will charge any HART 20V battery at 3x the rate of the standard 0.5 AMP charger. 20V Brushless Angle 4-1/2 Grinder/Cutoff Tool is great if you need a powerful cordless tool for a variety of grinding applications. Brushless Motor Technology provides up to 9 200 RPM and over 25% faster cutting!