Bass Neck Straight Edge (Notched) Luthiers Tool Designed to check bass guitar neck straightness of the fretboard and not Just the frets. One side is for 34(Fender) scale basses, and the other side is for 35 (most 5 string) scale basses. Works with most electric bass guitars. 6061 Aluminium- Nice Brushed Finish Machined Edges for Flatness / Cheaper Tools Ae Not