Philips Norelco SH91/52 Replacement Heads

Apparently, the Norelco 9000 series razors have 2 generations for the razor head shape. Gen 1 is round and Gen 2 is the pentagon shape. BUT, regardless of generation, both apparently have the same round razor heads. Who knows why the marketing folks would show the Gen 2 razor head when what they are selling works for either generation. And, it is only the 3 round heads and the 3 round guards!!!! What has changed is JUST the round razor guard and the round razor head (set of 3) come in this package. It no longer contains the whole razor head or the top piece (which holds the razor heads). What you will keep when switching out your old heads for the new are the top holder for the razor heads and the guards (mine were metal and twist off and on). Confused? I was. Why would the picture show parts that are in the box AND parts that are no longer provided????? I have used this product for a week and can attest it works great! I have had my Norelco 9000 series for 5-6 years and this has to be the 3rd replacement for the razor heads. I was so frustrated with Norelco because this series is very pricey--much more expensive than any of the prior ones I have used in my nearly 50 years of shaving. And no longer includes the parts they have included for decades (top blade holder and the locking rings to secure the razor heads).... Hopefully Norelco will keep this replacement part in stock for many years!!!