I have used this filter in my shop vac for the last several years, and it does pretty well. The filter is designed to keep any dirt and dust in the tank of the vacuum instead of getting blown out the other end of the vacuum. But the filter itself is also a little bit slippery, which makes it difficult to use in the vacuum. It is only held in place by a plastic ring that is pushed upward. Nothing holds the ring in place, and when the filter is somewhat slick, it is easy for it to slip down and fall off. When this happens, dust is blown back out the other end of the vacuum. When it stays in place correctly, it filters out dust well when using the vacuum in dry mode. It is also easy to remove when switching from dry mode to wet mode (my shop vac can do both). One of the downsides is that it is rather difficult to clean. Dust gets ground into it, and it is hard to shake or rub the dirt out. So it does need to be changed pretty often.