This is a shim kit for use with Overhead and First Class Parlor guitar. It works with models such as PJ410, and PJ410N and all similar models. These shims can be used temporarily and can be reconfigured according to how your guitar changes with temperature and humidity. They can also be glued for permanent installation. For installation instructions, visit our Shim Kit Installation page here: https://journeyinstruments.com/shim-kit-installation-guide/ *Please note this shim kit for the PJ410NE does not have a medium sized shim due to the shortness of the neck slot.