Black TUSQ XL is designed to boost guitar tone and performance. This precision engineered nut is made with a specially formulated material which couples the strings' vibrations to the neck and brings out the hidden harmonics and richness in every note. It is based on the highly resonant TUSQ man made ivory, but is impregnated with PTFE to improve the tuning performance of the guitar. The PT-6060-00 is a great option to upgrade the nut on your Epiphone Guitars made before 2014, and other popular import guitars.  The PT-6061-00 is a slightly taller version. It has a flat bottom and is pre-slotted for a quick and simple install. 15" Radius