GrAph Tech PQ-1530-00. This a great option to upgrade or replace the nut on your Mandolin.  It is pre-slotted to make for a quick and simple install. This nut has a curved profile to the top. TUSQ delivers a rich tone, crystal clear bell like high end with big open lows and a significant increase in harmonic content and harmonic sustain. Increase harmonics equals more richness and character in your tone. ?Its the difference between a four piece choir and a twelve piece choir singing every time your play a note. Please note that all Graph Tech nuts are slightly long and wide to ensureextra room to achieve a perfect fit for your guitar. This extra material can easily removed with fine grit sandpaper.