Proprietary two-piece string retainer (with 2 screws) for use on all Overhead travel guitars with 1.75″ nut width, for both wood or carbon fiber. POM Material, two-piece. *This is an upgraded design with increased thickness and strength to replace thinner string retainers used on earlier models. This is suitable as a retainer replacement for OF410, OF420, OF310, OF510, OF660 and all colored carbon guitars. It is not suitable for gutiars with narrow nuts, namely OF410N – or any collapsible guitar with “N” as the last letter. Note: Lefty string retainers are produced via CNC on a one-off basis, which results in a much higher retail price.