Craftsman Users: This filter will fit most Craftsman® brand vacuums (1988 to present brand, 5gal+), if you are looking to replace your red-stripe filter, part # 17816 then this filter will be just what you need. NOTE: If your current filter has rubber across one side that snaps over a ball then please contact us prior to order as you will need to order our Filter Adapter Kit! If you are not sure if our filter will fit your Craftsman®, a good indication is if your current filter uses a filter cap + wingnut to secure your filter onto the filter cage, if this is the case then our filter will fit your vacuum. If you need to replace the cap and wingnut we also sell those! If you have any problems with the filter fitting your vacuum please feel free to contact us and we would be happy to help. Ridgid Users: This filter will fit some Ridgid® brand vacuums, if you are looking to replace your vf4000 filter which is open on both sides then this filter will be just what you need. NOTE: If your current filter has rubber across one side that snaps over a ball to secure onto vacuum, then our filter will NOT fit your vacuum. If this is the first time you are ordering a filter for your Ridgid® vacuum then you will also need to buy our reversible cap and wingnut to secure our filter onto your vacuum. When you try to assemble the filter onto the vacuum and the cap does not fit, try flipping it over to the other side. If you have any problems with the filter fitting your vacuum please feel free to contact us and we would be happy to help. The dimensions of our filter are 8 1/8" high with an interior dimension of 4 3/8" and an outer dimension of 6 1/2". If you are unsure whether our filter will fit your vacuum, please contact us through your Amazon home page. *This product is manufactured by Kopach Filters, LLC. This is not a product of, or is it sponsored or endorsed by, Craftsman® or Ridgid®. The Craftsman® and Rigid® names are registered trademarks.