WORX WA3520 rechargeable battery

20V MaxLithium Battery Our all-new, cutting-edge MaxLithium technology gives you the same great features of any lithium-ion battery - with 50% more runtime than an 18V model! Forget about self-discharge, as you will experience full power until the end of the battery charge. Don't worry about leaving this battery on the charger, because there is no memory effect. This 20V MaxLithium battery is our most powerful and longest-lasting battery ever offered!