- 818 Posts. Joined 7/2002
- Location: MA
- Select All Posts By This User
Nah the Cera Nova X are full on replacements - the transition was made back when CH05(X) came out.
Anyhow, they're supposed to be slightly harder/more durable at the bottom end of each range. Which, IMO, was sorely needed for the previous '7' tier.
BTW, you do know to look for the X on the packaging? Some retailers still have their websites say 7 - including Amazon: