90 series had intermeshing 6 knife rolls.

Early 600 were opposed 6 knife.  Late 600 you could get 6 opposed knife or  6 knife intermeshing.

The 700 series now offer 10 knife intermeshing or either of the 6 knife rolls.

The intermeshing knife are more aggressive than the opposed.

The Calmer were 8 bladed rolls and he just introduced a 12 bladed roll.