Choosing a Harmonica by Comb Type 

The comb, aka reed block, of a Harmonica is the structure which the harp is built around.
It serves as a mounting bracket for the top and bottom reed plates, and also supports the top and bottom covers.
It’s fingers serve as channels for air to pass through over or under the 20 internal reeds.
Here, I’m talking about 3 different comb materials; plastic, wood, and metal. I’d say that all three can and should be used in a professional harmonica, because all 3 have their own particular strengths and weaknesses.
Comment below to add your insights into what makes a quality Harmonica comb!
Merci beaucoup!
Jason