GraphTech Tusq ~ Man-Made Ivory Guitar Nuts GRAPHTECH TUSQ NUT SLOTTED - MARTIN STYLE 1 3/4inch Guitar makers and players agree... guitars come alive with TUSQ man-made ivory. TUSQ delivers the optimum frequencies from the strings to the guitar top, producing richer and fuller tone. TUSQ is simply more efficient at transferring vibrations to your guitar top, resulting in big open lows and clear bell like highs