This is the Kahler 6 string locking nut with string director. It has a width of 1 11/16" (43.mm) with a 12" radius. The string director, which may or may not have the Kahler logo, is mounted on the base just behind the clamping plates thus eliminating the need for a string bar or string trees. Rounded string bumpers help guide the strings through the clamp plates and on toward the tuners without snagging which greatly reduces risk of string breakage between locking point and tuner. The string director also prevents string from rubbing on the locking screw under the pad.