Schaller S-Locks

The Schaller S-Lock strap buttons come in three sizes:

S (Small): Designed for guitars with smaller strap button holes.
M (Medium): The most common size, suitable for a wide range of guitars, including many electrics and acoustics.
L (Large): Used for guitars with larger strap button holes or where extra strength is needed.

For most standard electric guitars, including the Gibson Les Paul, the M (Medium) size is typically recommended.