Graph Tech PQ-M169-00 TUSQ Martin Style Acoustic Slotted NutThe M169 00 is a TUSQ slotted nut specially designed for Martin style guitars and others with similar specifications. 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. Dimensions in