Used this today for the first time on my K3.550 washer. This is a great piece of kit. Removes thick grime with ease, but it also removes loose paint from metal and stone so beware if you are going to clean the likes of a painted garden ornament. Although it is a pencil jet, the circular rotating motion gives it a wider 'footprint' so it cleans larger areas relatively quickly. This is a 'must have' if you are cleaning slabbing etc, and is much better than a fan type lance.