Bought this as my old shaver head needed replacing. My old shaver head was RQ10/40 so I thought the new version may have been improved. It turned out to be worse than the old one. As I started using it, it kept popping off. I thought maybe I was not holding the shaver correctly, but it turned out to be the new head. I contacted Amazon, who promptly gave me a refund, without any hesitation. I don't know if the head I received was faulty or these new heads are not suitable for the shavers. I will have to think again seriously whether to try another one or get the original version of the head.