Something for your kitty to happily rub against.  Version 1 has smaller sharper teeth on the comb while version 2 has thicker smoother teeth and catnip pockets in the “ears” for a lickable puzzle treat. 

My cats prefer version 2 but my friend's cat prefers version 1.  I've seen my kitty, Coulson, licking the catnip pockets all the time.

Update:  Picture of my cat, Rogers, next to other wall comb.