It is the threaded insert that gets pressed into into the body wood to accept the standard Kahler post.

Length: 0.0000 in
Width: 0.0000 in
Height: 0.0000 in
Weight: 0.400 oz
Packaging: 0.0000 kg
Units in box: 1
Parts by Make/Model > Kahler Parts > 25xx Traditional - Fulcrum
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Parts by Type > Mounting Hardware