First of all, it is worth mentioning that every powerball, if you were to shake them, sounds like something is loose. This is because the rotor is not locked tightly inside the housing. If it were, it cannot rotate and the ball will not work. The slightly loose rotor is therefore as it should be.
The NSD Spinner is a precision manufactured instrument. Any dust or dirt that can collect in the rotor housing will result in reduced performance. In practice, however, this is limited to an increase in some kind of scraping or tapping noise while spinning. It is good to know that this noise is not covered by our warranty, as it is damage resulting from use. It is also good to mention that it has no effect on the exercise itself: the training, intensity and effect of the powerball remains the same. If you think it is because there is dust or dirt in the housing, consider using compressed air or blowing the inside with your vacuum cleaner. To do this, remove any speedometer or cover from the powerball, so that you have two open openings on your NSD Spinner.
If the scraping noise is experienced as too disturbing, it is also possible to replace the rotor rings for some models. In our web shop you can buy spare parts for the most common models. However, some versions (PB-588 models for example) cannot be opened. Replacing the rings (yourself) will invalidate the warranty.
We recommend that you always purchase a protective solution such as a powerball bag or carry case with every NSD Spinner purchase.