This is a foldable pedal exerciser that can be used as a leg or arm machine. The left-hand photo shows the unit unfolded and ready to use. The right-hand photo shows the unit with the legs folded for storage. The tension is adjustable using the tension knob as shown in the pics. The digital readout displays several measurements: rotation count, RPM, time in minutes/seconds and Calories burned. This is the same unit used locally here by physical therapy professionals and by nursing homes.
Amazon shows the price as $-0.01 because they are currently sold out. They will be getting more in, I am sure, and you should get one when they are again available.