I bought the njoy pro, unfortunately, wrong charger was packaged with it, the company supposedly is taking care of that. Anyway, the Attys fit really tight into the filter. When I went to remove it to see why i wasnt getting good "hits"...it wouldnt come out, i had to "grab" the threads with scissors, it finally pulled out, but the "cap" on the atty was stuck in the bottom, got that out, now im getting inconsistent hits big time...there HAS to be a better way to pull the attys out, i mean, what if i want to change filters?