If I delayed my feeling communicate on XL shaving heads that I had ordered was that I hoped the shaving effectiveness of these heads would improve with time. A month later, I can say that I regret this purchase: The shaving heads have never cut, they still do not cut and I think they will never cut. I even feel that they still cut worse than they replaced the old heads!
PS: For the record, I obtained other heads elsewhere and they cut perfectly ...