Sold individually, this clamp plate for Kahler string locks is rectangle shaped with a centered hole and #8-32 threads. The clamp screw passes through the base and threads into this clamp plate, pulling the clamp plate up, into the base. The base must be removed to change the clamp plates. A very small number early 80's string locks were keyed so these are designed with a cut corner to fit those rare cases, most of the time it doesn't matter where the cut corner goes.
There are 2 types of clamp screw, 8420 is the type used on 5513 standard string locks and the 8419 is used on the 5514 deluxe/pro string locks.
Fits the Kahler 5513 Standard and 5514 Deluxe/Pro String Locks, they are not for Kahler locking nuts.
Locking nuts (or locknuts) and string locks are two different types of locking devices that do almost the same thing.
Locknuts always sit at the end of the fret board and incorporate the nut, the slotted part on the neck where the string vibration stops. It's both a lock and a nut... it's a locknut.
String locks are slightly different because they are attached to the head stock downhill from the nut and is just the "locking" portion. In other words, they only lock the strings and the nut is separate so it's simply called a string lock.