With the Faber® iNsert™, you now have the option of replacing the tone robbing pot metal inserts in your Gibson® Nashville or Heritage® Schaller bridge equipped guitar with the highest quality, tone enhancing GERMAN BELL BRASS inserts on the market today (note: AGED GOLD are made from German steel). This system, with 4mm upper threaded posts, will allow you to use either the Faber® ABR-1 style ABRN model bridge, or our revolutionary Tone-Lock™ bridge. Includes one pair of STEEL studs and machined brass thumb wheels (gloss or aged nickel, gloss or aged gold), a metal installation tool, and a 5mm bolt to remove the old Nashville/Schaller bridge inserts. NOTE: The depths of the original bushing holes are almost always deep enough. However, in some rare instances the holes are too shallow to allow the iNsert to be fully inserted so that the flange is flush on the top of the body. Please measure the depth of the bushing holes and insure that the holes are deep enough so that the iNsert will install flush with the guitar body. Please see the installation video under the “HOW-To Videos” tab.