Alibaba and Aliexpress are famous for selling counterfeit stuff, but it doesn't mean that all they're selling are fakes. If I remember correctly, they also sell lots of legit items that are Chinese brands. Makes sure that you're 100% sure that they're legit before continuing on with the purchase. Though why not just buy from the source instead? Just to be extra sure. https://shop.bitmain.com/antminer_s9_asic_bitcoin_miner.htm