Hakko 907 replacement soldering irons are high quality and relatively cheap irons, and there are many compatible clones on the market. Arhi says there is only a slight build quality difference between the original and it’s clones, and they all work perfectly.
All of them use the same ceramic heating element with a PTC temperature sensor. He provided a pin-out for the original and the clones he could get his hands on. He also made a resistance to temperature table based off a clone he used for the measurement, but asks for your assistance checking his measurements if you have access to a original Hakko soldering station.