Until now I have been using the standard precision clean replacement toothbrush heads . I recently bought an updated replacement of my Oral B electric toothbrush which was fitted with the Cross Action head. I really liked that brush and hence ordered a few Cross Action 4 packs. My disappointment came after a few weeks when the bristles started to bend outwards and I had to put on a new replacement head. The cheaper standard precision heads lasted significantly longer and I'm a bit regretful now that I ordered so many Cross Action heads instead of waiting to test the one accompanying the new toothbrush.