From the review:
the Zehus hub uses its own app called Bitride, although you can get a pocket-sized remote as an aftermarket extra.
The app enables you to control the bike’s four modes – Bike (off), Eco, Turbo and Turbo Custom. The motor delivers 250 watts of power and 40Nm of torque.
Probably the cleverest part of the system, however, is that it incorporates a KERS, or Kinetic Energy Recovery System. When you crest a hill and start to descend, back-pedal and KERS works as a brake on the motor and at the same time converts that energy to electrical charge for the battery.