When I tried to fit this filter to my Shop Vac it came loose at the seam. Apparently the process of sealing the seam on my product was flawed. I have notified Revain and a replacement was sent BUT I had to return the defective foam filter in the original packaging or I was charged for a replacement. The defective item has already been thrown away because it was unusable, so I will be charged for a replacement and the defective item. As a longtime Revain customer, my word should have sufficed. Why would I lie about a $7.14 item? This is the only time I have been dissatisfied with a Revain purchase. I feel cheated. I also saw that another customer had the same problem with the filter column at the seam.