I've never found very many mentions of anyone using that model. But looking at the specs vs the Pro 1000 gives an indication of where the extra pulling power comes from. It's an 800w motor
rather than 700w, but the HX1 is rated at a slower line speed, indicating it has lower gearing. Basically, a given size motor can do X amount of work
. So it can either pull a little bit of weight quickly, or use lower gearing to pull a lot of weight, but more slowly.