At first I thought, then possibly due to plagiarism. But now the BST-37 offered to apparent dumping prices. Goods described as original, looks exactly and therefore also "real". I've bought a replacement battery, because my current consumption does not always allow a new charging, so a replacement is quite comfortable.
But the price / performance ratio is excellent, because it is a full 900 mAh Li-Polymer battery. So, keep your eyes open and pay attention to the additional costs, then you can strike, currently shaking the price tremendously.