Direct replacement adjustable neck reinforcement rod as installed in Gibson® guitars since the late '60s. Traditional "one-way" design: turn the adjustment nut clockwise to correct neck upbowing. Includes steel rod, hex brass adjustment nut, anchor nut, and "half-moon" washer that's barbed so it won't turn in the peghead access cavity.
Rod: 18-1/4" x .167"-diameter steel (463.55mm x 4.24mm dia.). Note: The threads on this truss rod are rolled in the manufacturing process, not cut with a 10-32 die. If you need a custom-length rod, we recommend our Traditional Truss Rod Kit.
Adjustment nut: 5/16" hex brass.
Anchor nut: rectangular steel, 3/8" x 5/8" x .092" (9.52mm x 15.88mm x 2.34mm); square hole fits the rod cap, so the rod won't turn.
Half-moon washer: 11/32" x 9/16" x .100" steel (8.73mm x 14.29mm x 2.54mm) with two barbs.