Fitkit fk 600 the big brother of fk500. The main difference between the two is that fitkit fk600 has movable handles.
Meaning while paddling the steel air bike you can work out your arms too. The handles move smoothly enabling you to workout your whole body.
There is a 3 kg flywheel which is expected from a airbike from this price range. Since it is an airbike, air is being used as resistance and you will feel the breeze from the fk 600 while doing workout.
3kg is not too strong resistance so if you want to get stronger then get something like with 5-8kg fly wheel.
Otherwise for elderly and for easy workout that help with weight loss this fk600 will work.
It also has a digital meter with usual tracking of distance, calorie etc but better get a fitness tracker.