Many clarinets tune better when pulled at the center. Additionally, most clarinets are manufactured with a .5mm gap between internal faces between center joints when fully assembled. It is our view that this gap creates acoustic inefficiencies which hinder your sound and intonation. When the gap is filled, the resonance increases, the response becomes cleaner and the blowing feel becomes more uniform.  
 
BEHN acoustic spacers allow you to fill the gap when pulled at the center. Each Spacer Kit comes with  four pairs of tuning rings (one internal ring, and one external) in four different thicknesses; 0.5mm, 1.0mm, 1.5mm, and 2.0mm thicknesses.  

3D-printed