Check the listing for details. Truss Rod Dual Action Steel 8 3/8 adjustable Mandolin Bitterroot 081232. Condition: New. Listed at 10.99 USD. Truss rod for mandolin buildersDual Action adjustable Rod is for inserting in neck while building. Dual Action rod 8 3/8" LongDesigned for Mandolin and other short scale instruments. Specifications: 8 3/8" Length (212mm) Two Way Dual Action adjustment Uses a set of dual screw threads (one at nut, one at end) 4mm Allen key head Rod is wrapped in blue shrink wrap to allow for gluing or silicone set.Requires: 1/4" wide slot .36" depth (slightly more than 23/64") Cut for nut area is the same as the rest of the rod.Wrapped two way adjustable rod 8 3/8" length (varies slightly due to construction 8 1/4" - 8 3/8") Rod length is tip to end of nut.A PDF Version of the drawing for this is available, please email us for information.PLEASE NOTE: We recommend you bench test the rod prior to installation in your neck. While we do not have many issues with the performance of this rod, but it is a good idea to check the rod prior to installation. Bench testing can be down by placing each end of the rod in a vise and moving the rod in a normal range of motion and beyond to check the rod. After installation the rod can be very difficult to remove or repair. We test all rods here in the US, but we do suggest this additional step to insure the rod is working correctly prior to placement in the neck. Warranty for this rod is limited to replacement of the rod.or a refund on the product itself. Bitterroot Guitars is not responsible for repair or replacement of any guitar or neck due to installation or product failure. Warranty is limited to replacement or refund of the rod itself and the original cost of the rod. Any modifications to the rod void this warranty. Please contact us if you have an issue with any of our rods.