On one end is a "banana" plug that goes in your charger. On the other end of one pair of leads (when you buy them, they come in pairs like that.. one for a TX and one for an RX) you have a typical Futaba type servo type (sorry for the redundancy) connector. In the case of that picture, I think that it is Hobbico...probably Futaba, but pretty much universal. No, looking at it, it says "EA"..whoever they are.. but it is just fine for this application.

As long as RED goes to RED, goes to Positive ( + ) on the battery and the BLACK goes to BLACK goes to the Negative ( - ) on the battery, or the battery pack.. you're all set.

If you look clusely at any typical RX battery pack, you will see four cells connected in series. The connections are 'welded' in place and done very quickly so as not to damage the battery internals with the heat. My telling you this is because the typical packs consist of the type of battery you are working with here... so it will most likely take a quick charge (1C at MAX!!! or no more than 2.1 Amps) and it will charge in one hour or a little longer.. (10% overhead so make that about 1 hour and 6 minutes or so). It is always best to slowly charge batteries.. 1/10C is just about right, and they will last longer.. but 1C will most likely work.

CGr.