I have together with the bought the Astra blades Edwin Jagger Safety Razor. The blades are very sharp and shave thoroughly, but unfortunately they are with me anything but Skin Comfort. Even with great caution arise many small cuts and skin irritation on my neck. After several attempts with different Astra blades from the pack I've tried the Derby Extra blades, which the Edwin Jagger inserts. The result is significantly better shaving, no more cuts, but at least as thorough as the Astra blades.