The difference between the "Profile 88" and traditional mouthpieces is in the exterior angle of the beak. The Profile 88 has a longer, lower slope than most traditional mouthpieces making it more comfortable for some players.
The "Profile 88" series mouthpieces were also created for American players tuning to A440.
The Lyre Model is more open, the same qualities as the M13, easier to play in the upper register. It's facing gives it a partgicularly pure sound.
Fantastic clarinet mouthpiece for a serious player!