Bleached and unbleached nuts in various standard Martin sizes. For unshaped nuts, all sizes are minimum measurements. Please note that the pre-shaped and slotted nuts will need final fitting to your guitar. They are not a 'glue it in and go' solution. But they do cut down on the donkey work and reduce the chances of making a mistake! Note that some Martins have nuts with angled bottoms (parallel with the face of the headstock) - others have flat bottoms (parallel with the fingerboard).