I manufacture the original Sjoeberg 3D-Milled Custom Combs, which give the harmonica a performance boost. They are 3D CNC milled with a very complex design. Aerodynamic slots with mirror-wise progressive compression ridges direct the airflow against the reeds, causing easier bending and overblowing. Players describe a louder and crisper sound. The combs have a unique system with internal brass-tube resonators that are reamed into place to ensure a perfect fit between the wood and the brass tube (option). The resonators connect the brass element of the top and bottom reed plates and enhance the vibrations and overtones. The Sjoeberg Comb has taken over 10 years to research and develop, and each comb is milled to order by me in my workshop. If you plan to install a Sjoeberg Comb, I do recommend that you flat sand the draw reed plate for best results.