When I swapped out the stock filters for these, I immediately noticed that the motor sounded odd, like it was working harder. So I put the old ones back in and the problem was gone. I still haven't found a replacement for the Shark brand, I'm still using the old one that came with the vacuum. Not happy the difference was so noticeable and these guys will probably get away with it because few will realize that the vacuum works MUCH harder causing the engine to fail sooner than if you used a better filter.