This is the replacement upper bout indicator for 4-string NS Design WAV violins manufactured in China. If the bout for your WAV-4 violin is missing or broken, this is the part that you need
Replacing the upper bout indicator can be a little tricky, as the small metal pin that holds the upper bout indicator in place is installed last. The upper bout indicator is attached using only the thumb screw, then moved into the correct position. A hole is then drilled through the top of the bout and into the body of the violin to position the pin that holds the upper bout in place.
To install a *new* upper bout, lay a thin piece of paper (parchment or tracing paper works best) over the thumb stop area of the violin's body, where the upper bout goes. Using the edge of a pencil lead, trace over the paper, pressing down slightly. The tracing will clearly show where the hole for the thumbscrew and the hole for the pin are; you can then use this as a template to drill the pilot hole for the metal pin, after you've attached the bout.