The guitar bridge doctor (JLD Bridge doctor)

fixes under the bridge and the long post pushes against

the back of the body, flattening bellied soundboards and 

enhancing the sound,

Brass screw type is used by replacing the bridge pins 

with the brass nuts, which are holed for the strings to fit through.

Single screw type comes with a white disk to hide the screw head

mixed reviews of these but the gist

seems to be that they are a bit fiddly so get working and

If you overtighten them the thread might strip.

I'm trying to keep my prices as low as possible so if

You are likely to return it can you buy it from anazon.