Features a 1/4 inch nut driver on one end and a handy screwdriver at the other. Please note that Nylon Series and older Big Baby truss rods are accessed through the soundhole and require our longer wrench. Truss Rod Wrench. We generally recommend that you consult an experienced repair technician for truss rod adjustments, but if you know what you're doing, a truss rod wrench is a handy tool for tweaking the amount of relief in your neck. Use it to adjust for different string gauges or to dial-in the right feel for your playing style. Material: Metal Package Contents: 6 x Wrenches Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.