The g-string (and the b-string a bit) was really bugging me on my Epiphone Les Paul. Tried locking tuners and lubricating before, but didn't quite help.
This one fixed it just like that. Very easy to install, didn't have to take the strings off even. Just loosen the strings, and then switch the truss cover with this one. Bam, magic.
Only negative thing is that it looks a little cheap maybe. It doesn't have the embossed logo as in the picture. I can live with that. No need to tune the g every other minute outweighs that by several orders of magnitude.