I have used my Philips shaver for over two years and, although I usually use the same cutting head for a good number of years, decided to replaced mine with the latest cutting head, the RQ 10/50,for my shaver. Replacement is easy as the cutting heads come in a complete unit which click on to the shaver body. The shave is good,especially in the neck area. How much an improvement there is from the original heads, the RQ 10/40, is difficult to say as they gave a good shave too. I purchased the new cutting head at an excellent price on the Amazon Marketplace and I am very satisfied with my purchase.