JLD Bridge Doctor, Brass Pin Mount, for Flattening Bulging Guitar Soundboards A unique solution to a common bridge problem, this spruce device attaches beneath a guitar bridge An adjustable spruce "pressure post" rests against the tailblock, providing leverage to flatten the soundboard Better bridge contact and alignment can also enhance sound projection This pin-mount version attaches beneath the bridge using a threaded brass bridge pin, and the strings mount horizontally through the tops of the matching brass bridge pins (included) Installation instructions included