Many of the leading manufacturers and hand builders attach necks to bodies with this system. Bolting a neck on is quicker and easier than using a dovetail joint and allows for fine tuning of the neck angle. In the event a guitar needs a neck reset, it is relatively easy to remove a neck that is bolted on compared to one that is attached with a dovetail. These inserts have an coarse thread on the outside to hold in the end grain of the flush-mounted heel or tenon. They have an internal threaded hole to match the bolts. The conical Belleville washers on the guitar set compress when the nut is tightened and continue exerting tension, eliminating the possibility of the bolt ever loosening. - Set of 2 for Ukuleles - Includes installation instructions - Includes installation nut - High quality *The ukulele shown in the pictures is for illustration purpose only and is not included in the bolts & inserts set.