The Antminer s9 can’t just be plugged into the wall, it needs a PSU (power supply unit). So whenever you purchase an Antminer keep in mind that you will need to spend and additional $150 on a PSU.
The Antminer s9 has a "A mathematical process that takes a variable amount of data and produces a shorter, fixed-length output."> rate of 12.93TH/s -+ 7% (and not 14 TH/s as advertised sometimes), which means that it can generate around 0.5 Bitcoins every month. This is of course only revenue and not taking into account the electricity, "Miners that have grouped together in order to mine more efficiently with their mining power combined. After they successfully mine a block they split the reward between them fees, or hardware expenses. I ran the numbers against 3 different and they all show the same result. Around $330 a month of pure revenue.
Antminer S9 is best miner compared to other mining machines in the market.