The features that are of utmost importance to maintain within the life span of this product are the ferrite cores. It is important that the surfaces of each side of the ferrite cores are kept clean (which can be achieved using the alcoholic wipes provided), so that when the unit is clipped around a cable, the ferrite cores are touching each other. Failure of the surfaces to mate will cause incorrect readings to be measured and reported.
If the product appears to be malfunctioning, contact your dealer, or Pressac.