Dekra D-Drive Chainless Bike

The Dekra new bike - D-Drive System, which is a chainless bike. It’s very amazing, I now still wondering how it works without any chain?! Below is their official explanation:

How It Works
The Dekra D-Drive uses a drive shaft to transmit power from the bike pedals to the rear wheel. This drive shaft employs a fully-enclosed bevel gear system made of a lightweight, yet highly durable, aluminum alloy. Shimano internal gears within the rear wheel enable the D-Drive system to deliver smooth, quiet performance while optimizing pedaling efficiency. A three-speed Shimano “twist and go” gear system provides easy, responsive gear shifting operated at the hand grip. So there’s no more grasping for hard to reach gear shift levers!

It’s available with a price of USD300 at Dekra estore. In my opinion, for a regular biker, it’s worthful for the money to avoid the annoying chain jamming problems.