Thats a hub motor with a planetary gear. Like Heintzman or Rayben. I rode a Heintzman once,there a little noisy. They engage with a lurch. And it was very expensive. The Raybens have a website you can google. They are also on ebay.ca for I think 350US plus shipping, including 3X12v-12Ah SLA battery. I think they are 250watts so the speed is slightly less than GM. They look really nice. Draggin