When I first bought them I was very impressed and they fit my N681 perfectly. This last order did not match. The foam cylinder seems to be a bit narrower, so the vacuum is not sucked properly. It still works, just not fully. Unfortunately I bought these to have on hand so I didn't open/use them until the return window had passed so I couldn't exchange them and make sure I didn't get the wrong item. I will order another brand to test next time.