Zero Glide ZS-20 Acoustic Guitar Nut for 12-String Acoustic Guitar Kit Includes: 1 Bone Zero Glide Nut, 4 fret sizes, instructions Length: 52.0mm (2-3/64in) Width: 5.9mm (15/64in) Height: 9.5mm (3/8in) Spacing: 41.7mm (1-41/64in)