Craftsman should advertise this as a must if you have vacuum that is older and doesn't accept the filter nut on the new filters. It really bites when your filter falls off and you are vacuuming something like saw dust or ashes. This nut screws right on to the filter frame stud and holds the filter tight. No more worry or mess!
After a year or so the plastic tabs inside no longer grab the threads on the stem part of the vacuum, and the filter just falls off. Was there something wrong with the old design? It worked flawlessly for decades. As a workaround a small (1/8" width) zip tie can be put on the threaded stem, and the small tabs on this nut will have something to grab on to.
Worked perfectly after I lost my original filter wingnut.