If you want a less expensive replacement battery for your BD cordless tools then you are probably searching for replacement Black And Decker batteries. These batteries work just about similar as the original one but with a fraction of the cost of the branded version. This is because you are not paying for the name anymore but only the production expense of the battery itself. It’s like a generic battery with the same specification as the original without the less essential features.
Not every replacement battery are good, some third party supplier who just want to gain money uses a very low quality components to lower its cost. What happens is the plastic casing and the lock mechanism easily breaks or cracks when you drop or bump it, making it worthless for just a couple of days. Some even reduce the volume of battery cell and actually don’t last long than it supposed to be. So, be cautious when purchasing a replacement battery, you may end up throwing away money instead of saving.
You should also examine the quality of the battery before buying. By visual examination, look at the quality of workmanship, by looking at the product you can already tell if it’s made of low quality material, check for cracks and any tale tell of poor workmanship. Second is, even if it’s only a replacement it should still have a warranty. If it breaks easily they should change it or allow you to refund the money.