I got this for my Dirt Devil Featherlite. Haven't changed the filter for a few years and realized it's about time - Shape: Very similar to the original filter but doesn't quite match. While the original filter was very tight on the canister mount, this one was a little wobbly. The filter has a rubber seal so I don't think it would have leaked air under normal conditions, but it did seem to move a bit when cleaning. I cleaned the mounting area in the canister and taped it with duct tape to give it extra volume. After that it sits quite firmly and doesn't slip at all when cleaning - Function: Definitely works better than one that has been around for a few years. The vacuum cleaner ejects less dust and does not heat up during operation. It's hard to quantify this other than "It works". Overall I took off two stars because I didn't have to change anything to make it fit and work properly, but it ended up working just as well as the OEM. My vacuum's body clearly states that it uses an "F1" type filter, which is what it claims to be. However, I think the worry was probably worth the money I saved by not buying a replacement at nearly double the price from the store. If you have a Featherlite vacuum and want to save some money and not have to worry about a small modification to make it work then I would recommend you just don't expect the OEM to fit. Otherwise look elsewhere.