Mu Uno (with coaster brake) by Dahon. Foldie + Fixie 😀
Taken from Wikipedia: First invented in 1898, the coaster brake, also known as a back pedal brake or foot brake (or torpedo in some countries), is a type of drum brake integrated into hubs with an internal freewheel. Freewheeling functions as with other systems, but when back pedaled, the brake engages after a fraction of a revolution. The coaster brake can be found in both single-speed and internally geared hubs.
When such a hub is pedaled forwards, the sprocket drives a screw which forces a clutch to move along the axle, driving the hub shell or gear assembly. When pedaling is reversed, the screw drives the clutch in the opposite direction, forcing it either between two brake pads and pressing them against the shell, or into a split collar and expanding it against the shell.