Brand new 3.7V polymer lithium rechargeable battery 21700 4000MAH, flashlight with 2.54 plug.

Batteries are a part of our day-to-day lives and make things easier for us. However, it's vital to choose the right ones for your needs. Saline, alkaline, lithium, standard or button cell, disposable or rechargeable: there's a battery to cater for every need. Read on to find the right battery for you.