Fully compatible with our 36V lithium ion system — and with up to 33% more battery capacity on a single charge** — BLACK+DECKER 40V MAX* lithium ion batteries have the power you need to get the job done.

**Using the 40V MAX* lithium Ion 2.0Ah battery vs. the 40V MAX* lithium ion 1.5Ah battery.

http://qa.blackanddecker.co.uk/en/Support/FAQs