The WORX 20-volt Max Lithium battery fits: WG151, 154, 155, 156, 157, 160, 163, 251, 255, 320, 321, 322, 323, 540, 545, 546, 629, 778, 890, 891, 918, 919, 920, 921, 951 Series. The 2.0 amp hour lithium technology charges quickly and powers your cordless WORX tool through the entire job, without waning or draining. Max lithium batteries are lighter, more efficient, and charge with no memory effect. Includes an indicator system to quickly and easily determine how much battery life remains....