A:Answer I don't know about your particular model, but I have had aggravation with mine. Because Philips' website recommended buying the Sh91 vs. Sh90 for all 9000 models, I purchased them. They are slightly taller than the ones they replaced and therefore the retention rings do not hold them in place. I contacted Philips and it has taken me approx. 2 months to finally get replacement retention rings. They are very modestly better and after much annoyance I think they will hold the blades in place. This is yet to be borne out. Obviously, there is a design flaw and to say the least, Philips was unresponsive multiple times.
