I chose the 500 electric brush professional care that was sold with a brush floss action I found too rigid. So I took the precision brush clean I found much less rigid, but at the end I tried the sensitive and this one is the best for me anyway. We feel it better brush all tooth surfaces without skinning. I was not satisfied with my first purchase of floss action, but I am happy with the money back guarantee at amazon, so I've tried the other two, now I am a follower of the sensor. When my brush will wear it is that I intend to order in the future.