A battery lead is the main black wire and red wire coming out of your battery, typically with a connector on the end of them. Since we assemble all of our batteries in the USA we can build your battery leads to whatever length you need for your application. For example, a battery going in a small RC car may not need very long leads to get from the battery to the ESC but, if a battery is going in a large heavy lift drone those leads may need to be a little longer to get from where the battery sits on the drone to the ESC.