I saw motor upgrade, and I half expected to see your lawn mower engine sitting next to the Nilfisk. 😉 I don’t think you’ll rest until you can turn on a vacuum and have it create a black hole! 😂
That "thing" in the top is the safety valve, which should release if the motor overheats. It allow to let some air in to cool down the motor. When motor is cooled down again, it can just be pressed down to ensure proper operation again.
